Welcome to the huberman Lab podcast, where we discuss science and science based tools for everyday life. I'm Andrew huberman, and I'm a professor of neurobiology and Ophthalmology at Stanford school of medicine. Today. We're talking all about fasting and anytime we're talking about fasting. We are also talking about eating because we all need to eat sooner or later.
We're going to talk about how fasting. And when we eat influences a lot.
Large range of aspects of our health, and well-being, both physical and mental.
So well, nowadays. Most people
are familiar with the term, intermittent fasting also, sometimes called time
restricted, feeding. I think most people don't really understand how that
process works sort of obvious, that intermittent fasting. AK time restricted feeding involves eating at certain periods of each 24-hour cycle or maybe even not eating 4 entire days in some cases.
But if you think about it,
everybody sleeps eventually and therefore, because people don't eat during their sleep, almost everybody is employing some form of intermittent fasting or time, restricted feeding. What we're going to talk about today is how particular schedules of time, restricted, feeding
can impact our health in
different ways. And when I say different ways, I mean, we're going to talk about how intermittent fasting AK time, restricted feeding,
impacts way.
Loss fat loss in particular,
muscle maintenance and loss and gain organ Health such as gut health and Liver Health.
The genome, the
epigenome inflammation sickness recovery and healing from
sickness exercise cognition mood and lifespan.
So we're going to cover a tremendous amount of information. I promise to make it all directly accessible, regardless of whether or not you have a background in biology and
Metabolic science or not?
I'm also going to talk about a lot
of tools. In fact, I'm going to discuss a number of tools during today's episode
that actually make it such that you don't have to follow any feeding schedule
or fasting schedule. Same thing. If you think about it
in any absolutely
strict regimented. Way meaning
if you were to only
eat during an eight hour period of each day, most of the time, but then occasionally eat across a 12-hour period.
Of the day in theory that could actually have pretty serious, detrimental, health effects. And yet, there are things that you can do to attenuate those negative effects. In fact, there are things that you can do and or take that can make it as if you did not eat at all. And so we'll discuss what those tools are. And in many cases for sake of Health weight, loss and performance,
making the body
think that it did not eat at all can actually be quite beneficial. So today, we're going to cover
mechanism and
We're going to cover tools before we do that. I want to highlight a
particular result that was published recently because it serves as a useful backbone as we wade into the conversation about fasting.
This is a study that was published in the journal cell metabolism, a cell Press Journal, excellent journal and the title of the paper is fasting blood glucose as a predictor of mortality
Lost in Translation, and I'll explain what the Lost in Translation. Part means in a
moment, but the basic takeaway of this study
I should mention that. The first author of the study is Pally, a guru.
PA. Lli. Why agur you Guru
Polly Polly. Yeah, Guru
at all. The
basic finding of the study is that in humans, higher blood glucose is
associated with mortality. And in fact, if you look at blood glucose resting blood glucose across the lifespan, what you find is as people age resting blood glucose.
Goes up. Now.
This is very interesting because for a long time, it was
thought that metabolism actually goes down as we age and, to some extent. That's true, but the reductions in metabolism are not nearly as robust as we once thought that they were across the lifespan. However, unless there's something done to mitigate the increase in blood glucose associated with the Aging. Almost everybody experiences a gradual but regular increase in resting blood glucose that predicts mortality.
Now, the title, as I mentioned is fasting, blood glucose as a
predictor of mortality Lost in Translation. And the reason that they included Lost in Translation in the title, is that what I just told you that increases in resting blood glucose predict mortality, or are correlated with? Mortality is true for human beings and for non-human primates monkeys, but the opposite is true in mice and so I thought it was
important to use this study as an example
of where studies and mice often.
But not always translate to humans and non-human primates. So today I'm going to be careful to distinguish. When a study was performed in mice, versus in humans.
Because it seems that at least when discussing feeding blood
glucose and other aspects of diet as they relate to health and well-being whether or not a study was performed in rodents or in humans, can be very important. In this case. The results were directly a hundred eighty degrees opposite to one another. In other words, in mice.
Nice resting blood glucose when down and it was associated with mortality, so lower blood glucose associated with mortality. Whereas in humans, higher resting, blood glucose was associated with mortality. And obviously, what we're mostly interested in is health and well-being of ourselves of humans. I'm sure there are some people out there that are intensely concerned about the health and well-being of my switch. You could imagine a few rare context where that's important, but obviously most of us are interested in human
health, so I'll be sure to emphasize when studies were performed.
In
humans versus in mice. Before we begin I'd like to emphasize that this podcast is separate for my teaching and research roles at Stanford. It is however, part of my desire and effort to bring zero cost to Consumer information about science and science related tools to the general public in
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Was centered around, how to be a more effective learner and teacher using the modern principles of neuroplasticity. So at the link in the caption for this episode, you
can go to what was called, the rethink education event and there I gave a seminar of about 20 or 30 minutes. Describing the modern Neuroscience of
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So check it out. It's in the caption to this week's episode,
and it will remain there. It's up on YouTube and I hope you enjoy it. Okay. So
let's talk about feeding fasting, health and performance.
And I want to just establish a
A few
foundational terms so that we're all on the same page.
First of all rather than talk about fasting or time restricted feeding. I'm largely going to talk about time,
restricted feeding. But please understand that time restricted feeding is just one side of the coin. That is a two-sided coin that includes fasting on the one hand, not eating and time restricted feeding. On the other hand. I may occasionally say
fasting but because fasting and eating established different
biological
In the body time restricted feeding is the term that I will use to describe the overall
plan of restricting. One's eating window as it's called to a particular phase of each 24 hour day, or in some cases, to particular days within the week because as you'll soon, learn there are aspects
of time restricted feeding AKA
fasting that involve eating every other day or eating one way for five days and then fasting for two,
Days and so forth, so I'll be very precise about what I mean and why? I mean it, but for the time being, I'm going to refer to time, restricted feeding, as a way to put an umbrella over this conversation. Second of all,
I am going to emphasize a lot of biological mechanism. If you've listened to this podcast before, you
know, that I always begin with biological mechanism. I do describe tools of how to implement those mechanisms, but I wholeheartedly
believe that. No,
In mechanisms and understanding how these processes work
gives you tremendous flexibility and understanding and control
over the processes of your mental and physical health. Whereas if I were to just
list off a menu of things to do and not to do, those will work, but those will not give you the kind of understanding that would allow you to navigate
through life, through travel, through dinners out through different exercise, schedules.
Whether or not you're one age or another age, male female
Etc. I'm giving you mechanisms so that you can
gain more control over the systems in your brain and body. Everything is timestamp. So if you want to jump to the Tutu's, you can certainly do that, but I
encourage you to hang in there for the mechanism bit. I will make it all very clear because if you understand mechanism, you are in a true place
of power and control over your biology. If ever, there was a topic that is controversial, especially on the internet, it is that of diet. And
Ocean, so I'm wading into this with a smile and in eager
anticipation of all the, but, but, but this and but, but
that and wait, but this showed
that, here's the deal. We need to precisely Define what it is
that we're talking about. When we talk about nutrition.
I'm going to give you an example of a study that was published a few years ago, 2018 by a colleague of mine at Stanford.
Chris Gardner, so
terrific professor of nutrition and has done a lot of important
studies on how nutrition impacts different aspects of Health.
This is a large-scale study. It was published in Jama, the Journal of the American Medical Association. One of
the very top-tier journals in the area of medicine and certainly for a paper on nutrition to show up there meant that it had to meet an exceedingly high
standard.
This paper where Chris is the first author, it's Gardner at all. 2018, Jama.
Looked at weight loss in people following one particular diet versus another particular diet. In, this was a 12 month, weight
loss study. So it was focused specifically on weight loss. Although they looked at some other parameters as well.
And the basic conclusion
of the study was that
there was no significant difference in weight change between people following a healthy, low-fat diet, versus a healthy
low carbohydrate diet with significantly more dietary fats in them.
This caused a lot of
ripples in the world of nutrition and nutritional science. And certainly in the general population because anyone that understands diet and nutrition would
immediately say, but wait, there, all sorts of different implications of eating one. Type of diet. Say low
carbohydrate higher
fat versus a
higher carbohydrate lower fat
diet and indeed. There are this study was focused specifically
on fat loss and on weight loss.
So as we discuss
time restricted feeding, we need to be very precise about what are the effects of time, restricted, feeding and of eating it in particular ways at particular times. We are going to emphasize again whether or not the study was done in Mysore, in humans in athletes and men and women are
both. But the study from Gardner and
colleagues is a beautiful study,
and really emphasizes that if one's main goal is simply to lose weight. Then it really
It does not matter. What,
one eats provided that the number of calories burned is higher than the number of calories ingested. However, anyone out there, who understands a little bit of biology,
or a lot of biology will agree that
there are many factors that impact that calories burned part of the equation.
Some of those are obvious.
So, for instance, amount of exercise, type of exercise
basal metabolic rate, how much energy
He won Burns, just sitting there. I've talked before on this podcast about neat, non exercise-induced thermogenesis where
if people bounce around a lot and fidget a lot, they can burn anywhere from 800 to 2000
calories per day. So their quote unquote, basal metabolic rate is actually much higher simply because their fidget errs, whereas people who tend to be more stationary have a lower basal metabolic rate on average. There's great science to support this
metabolic factors and hormones are also very important hormones such as thyroid.
Phone and insulin and growth hormone, and the sex story to hormones, testosterone and estrogen, those levels will also
profoundly influence, the calories out the calories, burned component of the calories in calories out
equation. So, if out there on the Internet or in listening to a
particular podcast or speaker, somebody says this is the ideal diet or
calories in calories out does not matter or calories in calories out is the only thing that matters. I think it's very important to understand that there are some
General truths such as calories in calories out
but that, of course, hormone factors and the
context in which a given diet regimen is taking place are exceedingly important. A good example of this would be puberty at
that time in life. Sex steroid hormones are changing profoundly in the body
as our growth hormone and other hormones
and much of
caloric intake is directed towards protein synthesis towards the production of muscle and bone and other tissues of the body.
D. And that's because of changes in hormones that we call puberty. So,
there's no way that we can drill into every aspect
of a given
feeding plan or feeding schedule that would allow us to tap into every aspect of the list that I
read out before weight loss, fat loss muscle, organ genome epigenome inflammation, exercise, cognition, mood and lifespan. But today we're going to be very precise about how time restricted feeding. It's very clear from both animal studies and
Studies can have a very powerful
and positive impact on everything from
weight loss and fat loss to various Health parameters. This is a
beautiful literature that's emerged
mostly in the last 10 or 15 years. And as we March into this literature, what you'll see is that there actually is a perfect diet for you on a given day and that perfect diet, for you on a given
day is contextual. Meaning it depends on
On what you did yesterday and what you're going to do tomorrow?
So there is a perfect diet for you. And today, I'm going to arm you with the mechanisms and understanding that will allow you to Define what
that perfect diet is. And will allow
you to eat on a schedule and we'll and to
eat the things that are going to best serve your goals.
So let's talk about eating and what happens when you eat? And let's talk about
fasting or not eating and what happens when you fast.
I did an entire episode on eating and metabolism, and hormones and other
factors that impact appetite.
We don't have time to go into all those details. Now, although you're welcome to listen to that episode as well. But we can briefly describe the overall
conditions that are set in the body when we eat and when we don't
eat
the key word, here is conditions if I can emphasize anything today. It's that what you eat and when you eat it.
Set conditions in your body
and those conditions can be very good for you
or very bad for you. Depending on when you
eat. In fact, when you eat is as important as what you eat. I'll repeat that when you eat is as
important as what you eat, at least as it relates to health, parameters in particular,
liver health, and mental health. Some simple rules about eating, first of all, when you eat
Typically your blood glucose, your blood sugar will go up.
Also insulin levels will go up, insulin is a hormone that's involved in mobilizing, glucose from the bloodstream.
How much your glucose and Insulin go up, depends on what you eat and how much you eat
in general, simple sugars, including fructose and fruit, but also sucrose and glucose and simple
sugars will raise your insulin and blood glucose more than complex. Carbohydrates, things like grains and Breads, and pastas and so
forth.
And Grains and Breads and pastas. And so
forth will raise your blood glucose more than fibrous carbohydrates, like lettuce and broccoli and things of that
sort protein has a somewhat moderate or modest impact on insulin and
glucose and fat has the lowest impact on raising your blood glucose, and blood insulin. So what you eat will impact, how
steep a rise in blood glucose, and Insulin takes place. And there are a number of factors that are related to your
Jewel
Health, that will also dictate how steep and how high that rise in glucose and Insulin will be for the time. Being, I'm leaving out people who have type 1 diabetes. These are people that don't manufacture their own
insulin and type 2. Diabetes is essentially insulin insensitivity. Lack of sensitivity to
insulin which leads to high blood glucose,
but when you eat, blood glucose goes up and when you don't eat blood glucose and Insulin go down,
The longer it's been since your last meal, the lower typically, your blood glucose and Insulin will be and the higher things like glp-1 glucagon-like peptide, one glucagon, being a hormone. That's also secreted
when you are in a fasted state or a low blood glucose State. It's involved in mobilizing various energy sources from the body including fat, through what we call lipolysis.
Using carbohydrates and potentially even using muscle as a source of energy. So
that's kind of a
fire hose of information about what happens when you eat and don't eat. But just think of it this way blood
sugar and Insulin go up when you
eat, they go down when you don't eat and other hormones go up when you don't eat. So there are hormones associated with the fasted State and there are hormones associated with the eating and having just eaten State.
Now, the most important thing to
Stand. Is that like everything in biology? This is a process that takes time. So insulin and glucose go up when we eat and it takes some period of time for them to go down, even if we stopped eating, they
will remain up for some period of time and then go back down. It takes time.
This is very important because if you look at the scientific
literature on fasting, on time, restricted feeding, it's absolutely clear that the
Of benefits, not just the weight loss benefits, but that the health benefits from time restricted feeding
occur because certain
conditions are met in the brain and body for a certain amount of time. And that gives us an anchor for from
which to view what eating is in terms of how it sets conditions in the body over
time. And if
that sounds overly analytic, I promise you, this is the simplest and best way to think
about any eating schedule or anything.
E, eating plan. So I think it's fair to say that in the field of nutrition. There are a few Landmark studies that serve as really strong anchors for building our understanding of what to eat and what not to eat. And when to eat depending on our goals, the Garner study, that I mentioned earlier is one such study in that, it says, if your goal is weight
loss. It really does not matter.
What foods you consume provided that you consume a sub maintenance, Clark died.
However, I want to emphasize again.
That sets aside issues of
adherence, meaning how easy or hard it is to adhere to a given diet. Some people find it much easier to follow a high-fat low-carbohydrate diet. Some people, follow follow a different diet because it's much easier for them to follow.
And some people are concerned with mental
performance and athletic performance. So
that study doesn't say there's
a best diet. What it says. Is that what you consume is less important than the amount.
Mount of food that you consume at least for sake of weight loss, not necessarily for sake of Health.
Now, the study that I'm going to refer to
next is what I would consider, the second major pillar of nutritional studies. This is a truly Landmark study. That was
carried out by Sachin Panda,
who is a professor at the
Salk Institute of biological
studies in San Diego, and absolutely phenomenal institution, and an absolutely phenomenal researcher. I've known such in for a number of years and I want
For size that the current literature on intermittent fasting and time restricted. Feeding can largely be attributed to Sachin and the work that he's done. There are others involved
to of course. And of course, time restricted
feeding and fasting has a rich history that goes back many hundreds. If not thousands of years in different cultures and
religions, but the science
of time restricted, feeding can really mainly be attributed to the incredible work that suction
is done and I'm
grateful.
All to consider him a friend, and a colleague and we consulted at length in anticipation of this episode. I also hope to have him on as a guest in the future.
The Landmark paper that came from sogdians Lab was published in 2012. This was a paper in mice, that set the
basis for studies in humans that came later and the title of this paper
is time, restricted feeding without reducing caloric intake, prevents metabolic diseases
in mice fed a high-fat diet.
So the title tells us a lot. It says that
What's varied in? This study is not what these mice ate. It was when they ate it,
and there were essentially four conditions in this study and the results are absolutely remarkable. So I'm going to walk you through the major results. What they did is they gave mice access to different types of food. There were four groups, one group of mice, had access
to just a normal Mouse diet. It would not be a diet that you'd be very interested in. I confess, I've actually tasted Mouse.
If you work with mice at all, you just have to do it at least once it
doesn't taste very good. It tastes like a very
Bland graham cracker cookie. And I confess that, I only had the tiniest little bit, but mice like that stuff.
And if you allow them to eat that stuff, what's called ad libitum
whenever they want. You just keep it in their food. 24 hours a day. They will eat sometimes and then they won't eat at other times.
Or in this case. They also had a condition where they gave them Mouse Chow in a Time restricted way just for a certain number of hours
each day for about eight hours.
Hours.
Or they gave them a high-fat diet. That was a separate group, got a high-fat diet at any time they wanted. So this was kind of the carnival for mice, because mice really like high-fat, highly palatable foods. And so they got a lot of goodies and high fat in their
food. And then there was a fourth
group that had access to the high fat diet as much as they wanted to eat, but only during a restricted time period of each 24-hour cycle. Now,
mice are nocturnal, humans are what we call diurnal. Actually. We're not really dire. Nowhere crepuscular, which means that were
Active in the morning and in the evening, not so much in the afternoon. But nonetheless, everything I'm going to tell you
is true. Also for humans and we know this now from Human studies. One of the most important things to take away from this study. Was that mice, that ate a highly
palatable,
high-fat diet, a great-tasting diet, but
only during a restricted, feeding window of each 24-hour cycle
maintained, or lost weight over time.
Whereas mice that ingested, the same diet,
The same amount of calories but had access to those calories Around the
Clock, gained weight, became obese and quite sick and as an additional second point. The mice that restricted their feeding window to a particular portion of eight hours of every 24 hour cycle
actually showed some improvement in important Health markers. And what was
even more incredible. Is that mice that only ate during a particular feeding.
Also experience some reversal of some prior negative health effects.
So this study really lit up the world
and got people excited about time. Restricted eating
again. They used an 8 Hour feeding
window.
The story around that 8 Hour feeding window is kind of interesting though. Not many people know this because wasn't included in the paper and there was no reason to include it in the paper not to out anybody, but it turns out that the reason they used in a tower feeding window and not a nine hour or a 10 hour feeding window is
because studies of this
sort are actually quite demanding to perform and require the constant presence of the graduate student or postdoc there to
ensure that the food.
In the cages at particular times and not in the cages at other times. And mice are really good at hiding Food. They'll even hide food in their jowls. And so there's a lot of work that has to be done to prepare for that 8, Hour feeding window and to make sure after that eight hour feeding window.
There's all the food has
been removed from the Cajun, from the jowls of the mice and so forth. And
it turns out that the
significant other of the graduate student, and or postdoc, I won't reveal who they were running this study forbid.
Their significant other the scientist from being in the lab for periods of time that were much longer than the 10 or 12 hours that were required in order to ensure this 8 Hour feeding window. So when we hear the eight hour feeding windows are holy they are not holy and
later. We are going to talk about how
eating for a time that's restricted to eight hours versus 10 hours versus 12 hours. For instance how that impacts various parameters like Health parameters and weight loss Etc. But the 8-hour feet
Window
was actually created because of a real-world constraint on the research and the relationship of the researcher performing, the research not because there's anything holy about an 8 Hour feeding window.
Now an important point about when the feeding Window
Falls within the 24 hour cycle,
it is very important that the feeding window fall during the more active
phase of one's day.
So for humans that's typically in the early part
of the day or the later part of the day, but not at night,
put very simply.
Simply there are a lot of data. Now pointing to the fact that eating during the
nocturnal phase of the 24-hour cycle is very detrimental to one's
Health. In fact, when we eat can
either enhance our health or can diminish our health. When we see light can enhance, our
feelings of well-being or can diminish, our feelings of well-being. I've
talked many times before about this on the huberman Lab podcast that during the daytime, you want to get as much sunlight.
Than other types of bright light in your eyes as safely possible, and then you want to avoid light in the middle of the night. It has detrimental dopamine, lowering effects can cause depression, cortisol increases, Etc. So when you view light is as important as the light that you view. And when you eat is as important as what you eat
in this study, they saw something
really interesting, which was that not
only did restricting food
to a particular phase of the 24-hour cycle.
A benefit things like lean body mass and fat loss.
And a number of Health parameters that I'll talk about in a moment, but it also anchored.
All the gene systems of the body and provided a more regular stable. So called circadian rhythm or 24-hour
Rhythm. You may be surprised to learn that 80%
80% of the genes in your body and brain are on a 24-hour schedule. That is they change their levels going from high.
I too low and back to high again across the 24-hour cycle. And when those jeans are high at the appropriate times and low at the appropriate times. Meaning their expression is high and low at the appropriate times. And therefore the proper rnas and proteins are made. Because DNA and goats for RNA RNA is translated into proteins.
When that happens, your health benefits
when those genes
are not expressed at the right times when they're high or low at the wrong times of each 24-hour cycle. That's when you get Negative health effects. This study showed that when mice restrict, their eating to an eight hour period within the most active phase of their 24-hour cycle,
many of the genes that are associated with these. So called circadian, clocks.
These jeans have names, like /, be Mal. Cry 1,
Etc.
Those so-called clock genes underwent, a very
regular entrainment a locking in to the proper 24-hour schedule.
And while this was in mice, we now know that
this also occurs in humans, I've said before on this podcast, and I'll say it again that light and when we view, light is the primary way in which these genes and the clock systems of our body, get organized or entrained, meaning match to the outside, light dark cycle. So viewing light early in the day and in the afternoon and as much as possible. All day.
Great. Ideally that sunlight avoiding light in the middle of the night, is also great.
It's great because it causes the
increases in particular genes, in the decreases in particular, genes, in every cell throughout your body at the appropriate times. The second most powerful timekeeper or design Gaber as it's called is food. And when you eat and in this study the
results, they saw. Underscore
this point what they saw. Is that the peaks in these clock genes,
I'm very regular and the dips in these clock chains became very regular and that led
to a whole host
of really important positive health effects. Conversely, when mice ate, whenever they wanted across the 24 hour cycle. These clock genes became really out of whack and the negative Health consequences were the downstream result of these changes in these clock genes.
This is now also been shown to be true for humans. So if you want to be healthy, you want your organ Health, your metabolic Health to be in trained properly. One of the most important things you can do is to view light at the appropriate, times of each 24-hour schedule and to not view light at other times of that schedule and to eat at the appropriate time of each 24-hour day. Now again, there are rare instances that we will discuss, when skipping entire days or entire 24-hour cycles, of eating can be beneficial but
Now, we're
talking about schedules of time, restricted feeding them, involve a
window of feeding, that falls
during your more active phase. So, during the daytime, putting aside people that work shift work during the day time, is when you want to eat and this 8 Hour feeding window provided a
very strong reinforcing signal that combines with light
to ensure that these genes are expressed at the appropriate times,
the short take away from this is you probably want to think about
and perhaps even
Engage in time, restricted feeding.
So, as I mentioned earlier, when mice can eat around the clock, bad things happen. And one of the bad things that happens is that the liver suffers, the liver is involved in all sorts of things, production of important, hormones, and other factors related to metabolism. And when mice
can eat around the clock, their livers got very sick, fatty deposits in the liver, other factors in the liver essentially, taking down the pathway of liver
disease. The time restricted feeding as
Really reversed that or lead in many cases to even healthier liver conditions and that's based on this study. But also additional studies also now in humans, so
restricting, your feeding to a particular window, every 24 hour cycle has clearly been shown now, in mice and in humans to
enhance Liver Health, which is wonderful.
How does it do this? Well, it happens because food intake as I mentioned earlier, set certain conditions in the
body that last for a period of time.
I'm anytime we eat whether or not we are a mouse or a human.
There's a period of time that's required for so-called digestion. But also gastric emptying and other processes related to breaking down that food,
and utilizing it. And that is an active process. It requires energy,
and that process of breaking down food involves certain cellular functions that if they're ongoing throughout the 24 hour cycle, or even extended too far.
Across the 24-hour cycle, meaning you're eating across a 14 or 16 hour and 18-hour window
that causes serious problems. And this is now been established because of the fact that it increases the expression of different proteins and genes in the body, such as tnf-alpha. And il-6.
Il-1. What are all those things? They are pro inflammatory markers. So the reason that the liver gets sick when you're eating too, often is because inflammatory markers are increased
these inflammatory.
Tory markers are not inherently bad. They're there for a
reason, but they are
there in order to respond to certain challenges,
immune challenges, or the ingestion of food in the breakdown of food, but then, I didn't in an ideal circumstance. They are
reduced in the period, in which there's no food present
in the digestive tract, or in which there's very little food present in the digestive tract. So, by eating around the clock, you're making yourself sicker, by eating at restricted periods of time. Each 24-hour day. You're actually making
Of healthier and you're activating certain
processes that can positively impact both. Wait, either maintenance or loss of weight will talk about weight gain a little later
and positively impacting things like Liver Health. Also, the expression of different things related to
Brown fat, the fat that increases your
metabolism. We will return to this also a little bit later and blood glucose regulation. So the takeaway from this study. In fact, there are many takeaways from this study. It's so wonderful.
Why is that Liver Health, bile acid metabolism, energy expenditure inflammation, liver metabolites,
many, many aspects of our health are impacted by when we eat. Not just what we eat, as we move forward. And we talked about intermittent fasting for a tower Windows, six, our Windows 12-hour windows, for all sorts of different intents and purposes. I want to start to
establish a foundational
protocol that
All of us. Any of us can use
in order to maximize your particular
goals. There are some absolutes within this realm of
time. Restricted feeding. Here are a couple of absolutes that you would want to consider first of
all.
It pays off in the metabolic sense and in the health sense and in the weight maintenance,
or loss of
sense to not ingest any food
in the first hour after waking
and potentially for longer. So I want to repeat that one of the key pillars of intermittent fasting. Is that for the first hour after you wake up and potentially for longer to not ingest any
food? Okay, the second major pillar, that's well supported by research.
Is that
That for the two and ideally, three hours prior to bedtime. You also
don't ingest any food or liquid calories for that matter
and we will talk about what it
means to break a fast and whether or not certain liquids even coffee and tea can break a fast etcetera in a few moments, but
just as a foundation, it's very clear from the research in humans that
not eating any food or ingesting, any calories, liquid, or
otherwise for the first 60 minutes after way.
Waking up each day and for the two to
three hours prior to your bedtime. That's ideal for the parameters that we've discussed earlier. All the different things like weight, and Liver Health, and metabolic health, and so forth.
The two, most common questions about intermittent
fasting are when is the ideal time for the eating window. Is it early in the day, the middle of the day or later in the day?
And how
long should that eating window? Be? Should it be 8 hours. We already heard? Why the eight-hour window was first.
Established as because of these lab
conditions and the conditions of the particular relationship of the graduate student involved
or should it be seven hours or six hours or 12 hours, turns out that there's some general
Frameworks that we can follow in order to answer these questions.
As we move into this portion of the discussion. I want to highlight a very important reference that just came out. Literally came out last week in the journal, Endocrinology,
reviews, and the title of this review is
time restricted eating for the prevention and
Management of metabolic diseases. Although the
data in this paper go. Well beyond metabolic diseases. This
is a paper from Sachin pandas lab. It's a very lengthy review with an enormous
table. That's beautifully organized that
scripts out all the studies done in humans.
Well over a hundred studies looking at time restricted feeding in athletes. Men. Women children, diabetes. No, diabetes, Etc, with detailed references and description of the out.
Hums spent a lot of time with its review even though it just came out recently and is a absolute
Goldmine resource. It is also the major resource for everything. I'm about to tell you, if you would like to delve deeper into the
material. So let's deal with this. First
question of when is the ideal feeding window? And
here again, we're thinking
about a schedule of eating that involves eating, at least once every 24 hours. Not to day, or three day or every other day
fast.
So it turns out that the answer to the question. When is it
best to eat?
Is actually best answered by thinking about the other side of the
coin which is when is it best to fast?
So, because we are fasting during sleep.
It's very clear that it's best to extend the sleep-related fast
either into the morning
or to start it in the evening. Now, this might seem kind of obvious, but
it's actually not so obvious,
you could place.
Feeding window early in the day. Middle of the day or late in the day.
Let's think about what happens when we sleep. When we sleep our body
undergoes, a number of different processes in the brain and body. In order to recover the cells and tissues. Many of you have probably heard of autophagy, which is essentially a
cleaning up a gobbling up
of dead cells and cells that are injured or
sick. And this is a natural process that occurs and it occurs mainly during
sleep. Although not only during
sleep.
Fasting of any kind does tend to enhance autophagy. It
is not the only way to create autophagy check conditions on a
frigid conditions can be created simply by following a sub,
caloric diet, and there are other things that one can do in order to trigger autophagy, but fasting does trigger autophagy. So when we're asleep,
the bad cells are getting gobbled up and eaten and the good cells also are undergoing certain repair
mechanisms. Mainly related to or at
Governed by those circadian genes that we talked about earlier, those clock genes.
So you're already fasting when you're asleep and how deep you
are into that fast,
depends on how long it
was since your last meal.
So if you fast early in the day, and you've been
asleep for five, six, seven, eight hours, I would hope somewhere between six and eight hours for most people is going to be beneficial. When you wake
up. I mentioned earlier that you don't want to
eat.
Or at least the first 60 minutes after waking, but we're you to extend that fasting to say 9 a.m. 10 a.m. 11 a.m. Or even 12 noon or
later. You are taking advantage of the deep fast that
you were in during sleep and certainly toward the end of sleep. Now, why do I say deep fast? Well,
because when we eat the clearance of that food from our gut and the processes in our cells and organs that are
related to digestion and the utilization,
Ation of that food takes about five to six hours. So if you eat a meal and that meal last
10 minutes, 20 minutes, or 30 minutes, or even an hour, and then you
stop eating. You stopped eating, but you are not fasting at that point. You can say you're fasting because you're no longer putting food into your
digestive tract, but you are not in a fasted State, you are not under conditions of fasting later. I'll talk about things that you can do to accelerate the transition into fasting.
So,
One thing is certain that you want you're eating window to be tacked or attached to your sleep based fasting in a way that makes
it easier for you to get into the fasted state for a period of time.
So we can view that point from the perspective of best better and worst. Okay. So if you are like
most people in you sleep at night and waking up somewhere around 6:30, 7:00 a.m. Or maybe even 8 a.m.
Let's say you were to push.
You're fasting window out, such that you started eating
at noon. And then you stopped eating at 6 p.m.
Well, then you're not eating from 6 p.m. Until. Let's say your bedtime is 10 p.m. But from 6 p.m. To 10 p.m. Your body is not yet in a
fasted State because you just ate
however, you're starting to taper into a fasted State before sleep, and
then all through sleep, and until the next morning, and
Late morning, you are actually in a fasted
State. Now. Most people find it very hard
to only eat in the middle of the day. So while that's best it's ideal for sake of the fasting related improvements in
health. It is not ideal and it's not
very applicable to most work and family and social situations. Most people eat breakfast with others and or eat dinner with others.
Some people eat lunch with others, but in general, it's hard to restrict your
feeding window to
Absolute middle of the day, but from a purely Health perspective in a very objective way. That would be the ideal
situation. Let's imagine a different
pattern of eating where the feeding
window starts in the
afternoon starts around 2 or even 3 p.m.
Some people don't have much trouble, or they can train themselves to get their feeding window out
to 2 or 3
p.m. And then they will eat until 10 or 11 p.m. Right. If you do the math, you realize that that feeding window is still pretty short. It's still constitutes what we would call.
Intermittent fasting or time restricted feeding, but assuming that they go to bed around 11:00 p.m. Or midnight. They are not actually
fasted in sleep
because for the first 6 hours or so of
sleep, may be 5 but probably more like six hours of sleep. They're still digesting the food that they consumed late in the night.
It does appear beneficial to grab ahold of
that. Sleep-related fast. Meaning you
don't want your
Feeding window to be too close to bedtime. And that's why we came up with this kind of foundational pillar that I discussed with such an earlier, which is
at least no eating for the first hour after waking, but
also no, eating, within two to
three hours, prior to bed and because we all need to sleep and sleep is exceedingly. Important for our health, of all
kinds, you want to prioritize sleep, but because we also have to eat. Then you start to think about this. And hmm. Maybe it's not so good to push that feeding
window, too late in the day, because
Cuz when you go to sleep, you're not actually capitalizing on the sleep-related fasting.
Now, it's not just the case that
it's easiest to fast while in sleep, although that's true because when we're asleep, typically we're not hungry or looking for food, or foraging for food, or wanting food, or trying to resist food. We're just sleeping.
There is something special about the fasting that occurs during sleep because it's associated with a number of
processes that relate to the so-called glymphatic system,
the movement of lymph like fluids and other fluids.
Through the brain, a kind of sweeping out garbage
disposal. If you will a clearing out of the metabolic debris and some of the autophagy that's associated
with bad processes in the brain.
So we could do a whole episode on this but
essentially during sleep and in particular during
fasted states of sleep.
We are undergoing a number of automatic cellular
processes that clear out debris from our brain. Enhance kick cognition, or at least offset dementia. This is now well established as well.
As a number of the same processes occurring in the organs of our body.
So what we're starting to see here is that there are a number of
constraints on when you can eat now, I would be remiss if I didn't acknowledge the social constraints in the real life, constraints.
Some of us because we want to eat with our family and
because our family, or our significant others, eat around 8:00 or 9:00 p.m. And that's the only time we're together. You have to eat late in the day and
that certainly not a sin. I'm not saying that's good or bad here. We're trying to establish if you
recall best bet.
And worse.
So from both a
practical and a health perspective, and a purely objective view of how intermittent fasting works and can benefit
us starting to eat each day, somewhere around 10
a.m. Or around noon and then allowing a feeding window that goes until
six or maybe 8:00 p.m. That seems to me at least based on the data and what I understand about typical.
Cultures where people
eat in the daytime and in the
evening that seems to me, like, the kind of schedule that will allow you to get the
most out of intermittent fasting time restrictive, eating,
but does not set you up to be really
out of sync with the social rhythms in most cultures.
If you think about it, from the perspective of say a noon to 8
feeding window, what you'll find is that you're able to eat lunch with others, if you like or
Self, you will be able to eat dinner at a reasonable hour
at least, in most countries in most cultures, eating dinner somewhere between 6:30 and 7:00 p.m. Is typical.
When you say a feeding window that goes until 8:00 that doesn't mean sitting
down to dinner at 8:00. That means your last bite of food or ingestion of any liquid calories was at 8 p.m.
Assuming that you go to bed somewhere between 10 p.m. And 1:00 a.m. That allows this tapering off or this transition from feeding to a fasted
State and still allows you to capitalize on the special period of fasting. That is sleep-related fasting. And again, I want to emphasize that the
fasting that occurs during sleep is vital and
Eating too close to sleep will
disrupt that fasting related
sleep. Now. There are a number of caveats and details related to this and there's an important caveat in detail related to people that are specifically interested in increasing or maintaining muscle mass. So first, let's talk about food, volume and food type and how that relates to whether or not you quickly or slowly enter a fasted State because clearly
Early. When we talk about a
feeding window that
feeding window could include any number
of different foods that could involve cake and ice cream. Pizza hamburgers,
plants fruit, whatever it is, or it could
involve just fats or just proteins. Etc.
There are at least three factors that are going to govern how quickly you transition from ingesting food to a
fasted State. Remember, as you ingest your last bite or sip of calories. That's not when the fast begins, that might.
In the fasting begins on your
watch or on one of these apps that I'll refer to later which can help you track your
fasting and eating windows, but that's not when it actually begins because your body is still seeing food. You're actually carrying around
food inside of you even though you're
not putting it into your
mouth. You're still eating in some
sense. So, it should be somewhat obvious that
very large meals, are going to take longer to digest and very small meals. So that will impact how slowly, or quickly you migrate from a
A Fed state to a fasted State.
There's no way I can spell out what exact volume of
food. You should ingest based on the size of your stomach and Etc.
But you're all familiar with being
extremely full, very full comfortably, full somewhat full or not feeling full and feeling
hungry. So learning to gauge food volume is important. Also foods that include some fats or a lot of
fats will tend to slow gastric emptying
time.
And depending on the kind of fat, it
could mean that a given meal is digested within three hours versus five hours or more fats might be a large meal. With a lot of fats has been can take five or six hours. A smaller meal with less fat is going to be digested more quickly. Consuming calories in liquid form is going to mean that gastric emptying time is going to be
faster. And then of course, there's the glucose and the insulin
aspect to it, which is that foods that lead to Big
steep Rises and glucose like Pierre sugars?
Then your glucose
Will drop. However, if they're combined with fats, then it tends to be more. Gradual rise in glucose. And it's more sustained, Etc. Fibrous foods will also create a more long lasting sustained. Release in glucose.
The important thing here is to
establish a feeding window that you can comfortably manage. Okay, meaning that on average, you can obey a six hour feeding window or an 8 hour, or feeding window or a 10 hour feeding window.
And then to place that feeding window
in a
Shal and life context that you can manage on a regular basis.
Now. There are two key points that have been gleaned from the
scientific data about this feeding window and when to place it,
and this is
based on a really important experiment that Sachin and his colleagues have been doing. There's a website that they have zero cost website called My circadian clock. You can go to this website, free of cost are a number of important resources there. But what they've done
is they've examined, the feeding
behavior of thousands of people
People will take a picture of the food. They're about to eat and it enters into their account, maybe your account. If you create one on my circadian clock and they do this over many days or
weeks. What's great about this. Is it establishes? What's essentially
called a feed ogram time in which people ate? And a number of important findings, have emerged from these phaedo grams across large populations of people in different time zones with different schedules, Etc. First of all,
Almost everybody underestimates. They're feeding window.
Meaning people who think
that they are on an 8 Hour,
feeding window or six hour feeding window when their data
are analyzed. It almost is always the case that they're actually on a feeding window. That's one or even two hours longer than they think. Well, how could that possibly be if people are taking their first bite at noon and they're taking their last bite at 8
p.m.? Well
that must mean that they are on that feeding window of a
Hours and it turns out that people cheat but they don't cheat in any kind of obvious way. They might have, you know, a glass of
wine after dinner or they'll have a
cup of tea in a little bite of a cookie. And so when
people are honest and they are honest in most cases for this
experiment, what you find is that most
people's eating window is actually quite a bit longer. So in discussing this with such in, in reviewing the literature, it's clear that if you'd like to be on a
10 hour feeding window
that you should probably
Elect an 8 Hour, feeding window
because there's always a little bit of a taper on either side of that, eating window. Very few. People are
extremely strict about these eating windows. It's just hard to do in the context of Life events and social Gatherings and and family and so forth. Okay. So as we build forward
your ideal fasting, /
time restricted feeding schedule, we now have several different rules that we can list out first,
at least, no food for the first hour after waking up at.
Just one hour
to no food intake, for two, and ideally,
three hours prior to your
bedtime.
Three if you want to select an eight hour feeding window, then you should probably focus on a six or seven hour feeding window. Because in reality, you're feeding, window is going to
be longer reality meaning, real life,
constraints. And if you'd like to be on a 10 hour feeding window,
you should probably select an 8 or a 9 hour feeding window because the way it plays out is that people almost always eat outside of their eating window somewhat. The
other nice thing about selecting a slightly
Shorter eating window, then is comfortable for you.
Is that it takes into account
that, as you take your last bite or your last sip of calories. There's this
time or taper before, which you are actually in a
fasted State and because you're eating different things on different days, presumably some foods, leave your gut more quickly, something spike, your insulin, and your glucose more than others. Sometimes, eat more fat sometimes less fat.
This allows you to fall. Well,
within the margins of the benefits of time restricted feeding that have been demonstrated in humans, which generally involve an eight-hour window or so. So I think this
eight-hour window or six hour, window is a good thing to shoot for, for most people, some people and we will discuss the exceptions, but some people truly are exceptions to this. They just require more food and along those lines. I just now briefly want to touch on some of the studies that have looked at
using a very
Feeding window of about four hours nowadays. A number of people are doing the so-called one meal
per day or are restricting their feeding window to just four hours or six hours.
And that turns out to be an interesting strategy
and the data around it actually are a little bit, surprising
one, surprising thing to LEAP out of this
massive literature review
on time, restricted feeding and humans. Is that
relatively short feeding Windows of say 4 to 6
hours, do produce a number.
Our of positive health effects, things like increased
insulin sensitivity, which we know is good. Remember, type
2 diabetes, is a
reduction and insulin sensitivity improvements in beta cell function and the pancreas decreased blood pressure decreased oxidative stress.
Decreases in things like evening appetite. So positive health effects, and psychological effects, in general. However, they either produce no change in body weight, or they tend to produce even increases in body weight. Now, of course, there's variation between
individuals and between studies, but this
is somewhat surprising. So The 8 Hour, feeding window seems to be very
beneficial across almost, all the parameters that we've discussed inflammation.
Weight loss fat loss, Etc.
And adherence, I should mention people's ability to stick to the diet. Seems quite good on this 8 Hour feeding windows,
but when people try and undergo very short feeding Windows of four to six hours. It seems that they are overeating in that four to six hours at least overeating
with respect to their metabolic needs.
Now, the contrast to this is the so-called one
meal per day schedule. Very few studies on one meal per day, one meal per day. Unless it's a very, very long meal and sort of feast, typically would not last four to six hours because it sort of depends on how you define a meal.
But when you look at the very few should emphasize again, very few studies on one meal per day. People typically maintain or lose
weight on the one meal per day
schedule. So what we can say, is that the 729, our feeding window,
Produces all of
the major health benefits of time. Restricted feeding,
as well as
being pretty straightforward for most people to adhere to on a regular basis. And on a regular basis, turns out to be very important. I'll get back to that point a moment.
Whereas the four to six hour eating window, doesn't seem to serve
people as well as say a seven or eight hour eating window. Simply because people are overeating during that eating
window and the one meal per day while perhaps
ideal for certain people's schedules. May actually cause
all to under e. And in some cases, that might be what people want. They actually want to under eat.
But when we start thinking about performance in
work and in sport, and when we start, considering Hormone Health, and hormone production
fertility, that's when we can really start to look at the seven to nine hour, feeding window versus the four to six hour feeding window
versus the one meal per day.
Type feeding window, with some
different objectivity. We can start to look at it through a different lens because it
Turns out that
when you place the feeding window and how long that feeding window is actually will impact a number of other things in particular hormones, that can be very important for a number of things related to sex. And reproduction can be related to performance at work performance in
athleticism. And there are excellent
studies on this. So let's explore those now.
So let's talk about some conditions. We're
having the feeding window early in the day would actually
be very beneficial. There
was a study that was published recently in cell reports again cell Press Journal. Excellent Journal peer-reviewed very stringent from aoyama at all. So, this
is a, oh, why am a at all?
This was published just
recently in July, 20, 21
that looked at the distribution of protein intake in different meals, delivered, either early in the day or later in the day, and I'm summarizing
Here quite a lot, but I should mention that this study was performed in both mice and humans. Same paper, mice and humans and involved. Hypertrophy training,
essentially, increasing the weight bearing of given limbs to try and induce hypertrophy, which is the growth of muscle tissue.
It does appear that muscle tissue is better able to undergo hypertrophy by virtue of the fact that there's better or enhanced protein synthesis early in the day because of the expression of one of these particular clock genes called B. Mel, B maal Be Mel regulates a number of different protein synthesis Pathways within muscle cells,
such that eating protein early in the day support.
Muscle tissue maintenance and or growth and in this study. They also looked at the effects of supplementing, so-called BCAAs branched chain, amino acids, Which is popular in bodybuilding circles and in strength, training circles, and
BCAAs are essential components of
a number of different foods, but can also be supplemented the take away. The study is pretty straightforward. However, the takeaway is if your main interest is maintaining and or building muscle,
then it can be beneficial.
Unofficial to
ingest protein early in the day.
You would still want to obey this.
What we're calling a kind of foundational rule of, no, not eating any food for the first hour? Post waking or at least the first our post waking, and the cutoff for when you would want to eat protein, would be some time before 10 a.m. And they're, I'm averaging across a number of different
situations. But in general, this be Mal
expression is such that, let's say you wake up at 7 a.m. Your main interest is
In hypertrophy or maintenance of muscle, then you would want to ingest some protein, some time before 10 a.m. But obviously, if you're interested in getting the health effects of intermittent fasting that you wouldn't ingest any food for at least the first 60 Minutes upon waking. Now, it's not as if at 10:01 a.m. A gate slams shut and you can't generate hypertrophy. Of course, that's not the case. However, it's very interesting that it doesn't matter when the resistance training the load bearing.
Sighs occurs in the 24-hour cycle. So whether or not in other words, people are training early in the day or their training, late in the day, it still appears that ingesting protein early in the day favors, hypertrophy or that one is better or I should say more easily able to access hypertrophy by way of these clock regulated protein synthesis mechanisms by ingesting protein early in the day
in, no way shape or form. Does
this study say that ingesting protein later in the day?
Somehow bad for you. It just emphasizes the positive effects of ingesting
protein early in the day for sake of muscle maintenance and or hypertrophy. So, if you're somebody who's mainly concerned with muscle maintenance and hypertrophy,
then it may make sense to move that
feeding window earlier in the day. And certainly, there are people out there who are interested in muscle maintenance and hypertrophy who aren't doing intermittent fasting at all. And that's also a perfectly fine. But this just so happens to be an episode about intermittent fasting and time restricted.
And there are, of course,
modes of eating where one eats small meals spread throughout the day, or weights meals differently. Such that meals early in the day are larger than later in the day or vice versa. There are a near infinite number of ways to organize this. But if you are, somebody who's interested in deriving, the many clearly established health effects of time, restricted feeding and you are somebody who would like to maintain
or build muscle.
Then
injesting proteins in the early part
of the day would be important to you. At least on the basis of these results and therefore that eight-hour window that we we've established as more or less ideal shifted to the later part of the day, might not be as beneficial for you. Now. I can just personally say that for me when I wake up in the morning. It's a very easy for me to not eat until noon or 1:00 or 2:00 p.m. Eating early in the day is actually somewhat of a
challenge.
I discussed this point with such n because we were talking about how is it that one can move
their feeding window or place themselves onto a different schedule of intermittent fasting. And it's very clear that one needs to provide a transition period in order for that to happen. You should allow yourself a transition period of anywhere from one week to 10 days in which you shift your feeding window by about an hour each day or so, and then once you establish a feeding window that feels comfortable for you.
And that you think you can maintain over time, that you simply maintain that, feeding schedule for at least 30 days, but ideally, you would do that indefinitely.
Now, this turns out to be important Based, on data that they've
gleaned from this, my circadian clock, massive experiment, that they've been doing, where people are entering the times that they're feeding, and, and eating. Excuse me. Anytime we talk about mice, always think about feeding, because I come from a background in my lab. Works on both laboratory mice, and on humans.
And he's on my thing about humans, I
think about eating, but of course,
If they are the same thing.
The interesting thing to emerge from that very large
data set in humans, is that when people log their feeding times, as I mentioned before, oftentimes, they think they're eating in an eight-hour window, but they are actually eating in a much broader window. However, even for people that are very good about restricting their feeding to a 4, 6, or 8 Hour window. If they're very strict about the start and stop times when they ingest calories, one of the findings. That's really been important to
Note is that
almost every
individual has a lot of drift in when that eating window resides in their 24-hour period, in particular, on the weekends,
people are either extending or
shifting their feeding window in a way that makes it seem that they've traveled to another time zone and are eating according to another time zone. And
this is extremely important. As
I mention earlier,
based on the 2012 study from Sasha.
Lab, we're eating at a particular phase of each 24-hour cycle. Can help enhance the expression of these clock genes.
If you are eating
within a very strict or semi strict feeding window, but that feeding window is migrating around from day to day or five days a week. You're really organized about when that falls. Let's say for sake, of example, from noon to 8:00 p.m. Noon to 8:00 p.m. Monday noon, to 8 p.m. Tuesday, Wednesday noon day p.m. Thursday and so forth. But then on a
Saturday it's becoming 11 a.m.
And you're ending it early, or perhaps you're starting early.
In the day on
Sunday, you're having brunch that starts at 9:30 or 10:00. And then it's extending out, still just eight hours. But it's shifting around
that can cause disruptions in these circadian clock mechanisms that cause disruptions in the downstream
effects of eating that are taking at least two to three days to recover from.
So obviously
we don't want to be overly neurotic about this stuff. But because this is an episode about the science of intermittent fasting and time restricted feeding.
As important as
how long you're feeding window is, is where that feeding window resides in each 24-hour cycle. And perhaps,
even more important than that, is that
it be fairly regular where that feeding window resides. Because
even if you have a very short, feeding window, if it's drifting around, from day to day,
that actually offsets a number of the positive health effects of intermittent fasting. So to really just underscore the way that these different pieces of the biological puzzle fit together.
If you are very strict or semi strict about your eight hour feeding window, but on the weekends that 8 Hour feeding window is falling later than it, normally would drain the middle of the week. It is as if you are going to bed later, even if you're going to bed at the same time, at least from the perspective of metabolic health because of the way that eating impacts these clock genes and impacts or I should say sub tracks, the sleep-related fasting that you would normally experience if you were to finish.
In a couple hours before bedtime. So again, we don't want to create any overly obsessive or neurotic focus on this. I
think that most all
people could benefit from a Time, restricted, feeding schedule, but they should really think hard about what they can stick to on a regular
basis and understand that they tend to underestimate the
feeding window that they actually
are partaking in and that they should place that feeding window in a portion of the 24-hour
cycle that they can be consistent on most days.
Days, and I want to emphasize most again because we are not laboratory mice. We don't have a graduate student coming in for 8 hours a day because that's what their significant other will allow them to do. And then removing the food from our jowls and from our
cages, we have access to food, pretty much 24 hours a day.
Along those lines. However, there are things that we can all do. That will allow
us to offset some of the drift, if you will, that we experience or that we induce in terms of, when are feeding window occurs, or that the feeding window might push out a little later and then, therefore start a little later. The next day. There are things that we can do in there things that we can take. And so I'd like to discuss those briefly. So, throughout this episode. I've more or less been
alluding to the fact
that
When you eat, there's some period of time afterwards in which you're actually still eating at least from the perspective of metabolism because glucose is up, insulin is up and you're undergoing, different metabolic and digestive processes that don't really speak to you being in a fasted state, right? It's not just about when you take your last bite or your last
sip, however, there are
things that we can do to accelerate the transition from a Fed state to a
A fasted State.
And so, I'd like to discuss what those are. And I want to emphasize that the term fed state is
probably a better way to think about it, then, eating or not eating, because we think of eating, as the verb. We're eating reading. Okay, we're done eating. I'm fasting. Now, you're not actually fasting you because you are fed. So we should really think
about fed and unfed States
because from a cellular processes perspective and from a health perspective. That's actually what your body in your system are paying.
Chintu. And by now, with everything that we've laid out. I think that should be intuitive to
understand. So there's a fun and exciting
concept related to this, which is glucose clearing.
You may have heard the old
adage that if you take a 20 or 30 minute walk after dinner, that it accelerates the rate at which you digest that food. And indeed, it
does clearing out of glucose. From your system can be accomplished through a number of different means but light movement or exercise does
Increase gastric emptying
time. So for
instance, if you were to eat a meal that ended at 8:00 p.m. And 2:00 and then plop to the couch watch TV or get on your computer
or go to sleep. It would be five or six hours
until you have transitioned from a Fed state to a fasted State. However, you can accelerate that considerably by taking a 20 or 30 minute just Light walk. It doesn't have to be speed walking. It certainly doesn't have
Jogging but just walking outside or moving around. So glucose clearing is an important aspect of the transition from the FED state to the fasted State and just a light walk can allow you to do that. Now, if you can't get
outside, some people will go through
the gymnastics literally of doing things, like air squats and push-ups and things like that.
And indeed, those will increase the
expression of things like glut4 and things that mobilize glucose into muscles and things of that sort, but
You know, under most conditions, most people aren't doing push-ups after dinner or certainly. If you've had a big meal, just taking a light, walk can be
beneficial in addition. You could consider doing intense exercise.
Now you wouldn't necessarily want to do that immediately after
eating. So let's take a
look at what high intensity training of any kind does to blood glucose
because in this case it turns out that when you do
high intensity training actually has opposite effects on blood glucose, depending on whether or not you do it.
Lee or later in the day,
so a fairly recent study looked at so called Hit training, high intensity,
interval training, which of course can take many different forms. It can take the form of circuit training with weights. It can take the form of burpees and push-ups, and Sprints, and all sorts of doing things. But I intensity interval training is typically training that gets people's heart rates up,
you know, well, above 70 percent of Maximum and then
brief periods of rest, and then repeating and how long the high intensity interval training. Of course, will also vary.
There's there are very brief, you know, six or 12 or 15 minute workouts. Some people can carry on with high intensity interval training for up to 45, or maybe even 60 Minutes in extreme cases. But when you look at the studies that have explored high-intensity interval training and its effect on blood glucose, there are a couple studies that leap out.
For instance, one that emphasized that blood glucose
levels will actually increase if high intensity interval training. Is performed early in the day and will decrease if high intensity
Well, training is performed later in the day. Now, the purpose for this exploration
was not
to explore clearance of blood, glucose for sake of intermittent fasting. It was mainly focused on athletic performance and whether or not that was better early in the day or later in the day at cetera,
but we can extract some information from these studies that are beneficial for sake of understanding glucose clearing. If you have ingested food throughout the afternoon.
Noon and evening and late in the day and you're thinking about going to sleep and you'd like to enter
sleep in a way that is less fed and more
fasted. Then engaging in high intensity interval training in the afternoon will lower
or evening. I should say will lower
blood glucose. And in that way will help you accelerate your
transition into the fasted state provided. You don't ingest something after the high intensity interval training. Now
is the increase in blood glucose that occurs from high
intensity interval training
early. In the day is that
Detrimental not necessarily. So that often times is associated with the shuttling of nutrients to the muscles that have just done a lot of hard
work. So it's not that high intensity interval training should not be done early in the day. In fact for many people including myself training early in the day, just for the way that my psychology and biology works is always better for me than training later
in the day and the other important thing to mention is that high intensity interval training, done late in the day, can be beneficial from the perspective of glucose clearing.
Lowering blood glucose and helping transition from the FED to the fasted state in preparation for
Sleep. However, if you're ingesting caffeine
or anything to engage in that high intensity interval training in a way that prevents you from getting to sleep. Well, then it's going to be detrimental overall.
So the
reason I mention this is of course because it's nice to know that light walks after dinner or any other meal for that matter or
high intensity interval training
provided. It's done in the second half of the day, can lower blood, glucose and speed.
Transition from fed too fast, it's dates.
But I also mention it because what we are really trying to achieve. When we
partake in intermittent fasting, so-called time restricted feeding
is what we're really trying to do is access unfed
States or fasted States.
It's not really about when you eat and what you do it's about extending the duration of the fasting period as long as you can in a way that still compatible with your eating, right, not the other way around.
Around. And this gets back to this key feature of our biology, which is that what we eat, when we eat when we exercise, when we view, like it's about setting a context or a set of
conditions in your brain and body.
So it's not so much about the activities that you undergo. It's about the activities, you undergo and their relationship to one another over time. And so, in this way, it really beautifully highlights. The way that your biology is interacting all the time. Light
is setting when you're going to be awakened when you're going to
Sleep when you eat is going to be determining when you're going to be awakened, when you're going to be asleep.
And when you eat is also going to be determining when you are able to clear out, debris
from your brain and body and repair, the various cells and mechanisms of your body. When you're able to reduce those inflammatory cytokines throughout your body.
And this is really the beauty of timer circuit feeding, which is it's not really about restricting your feeding. It's about accessing the beauty of the fasted State. Now. There are other ways
to clear out.
Blood
glucose that involve supplements or prescription drugs. These are so called glucose disposal agents glucose disposal agents such as metformin, which is a prescription drug
or berberine, which is an over-the-counter substance will
lead to very dramatic reductions in blood
glucose. And so they shift you from a fed to a
fasted State. And I know many people who take berberine before
eating meals that include
Number of carbohydrates, for instance, as a way, to clear out glucose.
Now, I've tried berberine before, and what I can tell you is that
if you take berberine, which by the way, is very much like met form and its effects are almost identical to metformin, in fact, but it's much less expensive and it's over the counter. If you take berberine and you have not ingested. Carbohydrates,
many people including myself experienced a splitting headache,
you become hypoglycemic because it is a glucose clearing agent. So if you're going to experiment
Things like metformin and or berberine or similar. You want to be very
cautious that you're not clearing out blood glucose.
That's already low and the
dose response for this varies. Tremendously from one individual to the next and there's a strong circadian component. So some people react very well to berberine early in the day, but find that later in the day, it provides extreme headaches for some
people. It's the opposite.
So I caution you in exploring things like, berberine and
Metformin.
That you should expect to experience a number of physical and psychological effects.
That may work for you might be great for you, but might also not be great for you. Nowadays. There are a number of
commercially available continuous glucose monitors. I've tried one of these involves putting what's essentially a patch with a little needle that goes into your skin, which is continuing continually scuse me monitoring your blood
glucose and you can look at it at an app on your phone
and you can learn a lot that way about how different foods
impact. The increases in decrease in blood.
Those, if you're doing experiments with berberine or metformin, you can see how those impact your blood glucose. You can see how
exercise hit training or otherwise in Black impacts
blood glucose. Excuse me. Again, it's very hard to assess blood glucose without a continuous blood glucose monitor. And if you're not using one, you're mainly going to be relying on subjective. Things like, oh, I feel like I have low blood sugar, or, I feel shaky like, I have high blood sugar or shaky because you have low blood sugar. So,
I have to say,
That glucose clearing agents
that involve a walk or exercise moderate or intents
are going to be a lot easier to titrate and adjust the levels of then
things that you're going to take, where you have to adjust the dosage. And then once you ingest a certain dosage, you're along for the ride at least until the effects of that particular compound wear
off. It doesn't mean those things don't have utility. It doesn't mean people aren't using them because many people are, but
they are potentially a very sharp blade. That is a
double.
Sided blade. So I encourage you to
approach those with caution. If you decide to at all, it's worth thinking about what the low blood glucose state
is and why it's
beneficial as well as
why it might produce headaches. And in some cases can also adjust the effects of other hormones
in the fasted State, a number of different proteins
that are expressed in cells, undergo changes in their expression. We talked about this
earlier. When we are fasted. We tend to
reduce the activity of a particular
Allure protein called mtor. Mammalian Target of rapamycin. Mtor is a very active in cells while they are growing. So throughout development. It's also very active in cancers of various
kinds.
Mtor needs to be what's called phosphorylated. If you don't know what that means, don't worry about about, phosphorylation
is a manner in which certain
proteins are altered so that they can actually be functional within cells mtor is associated with cell growth
of all kinds healthy and
unhealthy.
When mtor is phosphorylated, there's a marker called
ps6. So phospho mtor expresses ps6. If this is all escaping you, don't worry about
it, phospho mtor and ps6 are reduced by fasting. Now. This makes sense, if you
think about it, because eating and growth are associated with each other fasting, is
not necessarily
anti-growth, but it is not pro-growth. And when
we fast, we see increases in cells of things like ampk, the
Two ends things like transcription factors, like,
foxo ATF and ketones or Ketone bodies. You may have heard of the ketogenic diet. What's the point
of all this biochemistry? It's not just Blitz you with a bunch of cellular
biology and biochemistry.
It's to say that we have cell growth Pathways involving mtor & PSX and we have cell repair and sell shrinkage
processes that are associated with ampk. This will call
sirtuins, which dr. David Sinclair from
Offered and others are famous. For discovering an understanding things like ampk these two different Divergent Pathways of cell growth and cell breakdown, and
repair. And by breakdown. I mean, actual clearance autophagy and repair.
Those can be triggered by being in either the
fed or the fasted state. So, one way I'd like you to
think about the FED State, not just eating
but having recently eaten or the fasted State, meaning high, blood glucose.
Or you've recently eaten or are currently eating or drinking calories. Is that
when you eat or when you don't eat when you're fed, when you're fasted, you are either promoting cellular growth of all kinds or you're promoting cellular repair and
clearance of all kinds. And so, again, this is about setting conditions in the brain and body.
It's not so much about when you eat food A or B.
It leads to increases them. In mtor.
Any time you eat any food? Doesn't matter if it's plant-based.
It animal-based fat, protein carbohydrate, doesn't matter. You are
biasing your system towards a biochemical state of cell growth. And
anytime you haven't eaten
for a while or blood, glucose is low your biasing, your system toward a state of cellular repair.
And this is why people who do
not suffer from any blood glucose regulation issues. Take things like berberine as glucose disposal agents or take Metformin. I'm not necessarily
suggesting that you do that, but it's because those things mimic
Fasting. They create situations in the body that
promote things like ampk in the sirtuins and others to
push your body and your system
down a route of repair, even though you might have just eaten a meal, an hour ago,
along the lines of the health benefits of intermittent fasting there. Nice data showing improvements in the gut microbiome,
and in particular, in the treatment of irritable
bowel syndrome and other forms of colitis
in time
restricted feeding, meaning
I'm restricted feeding seems to be able to assist people with those
conditions following the general parameters that I discussed before eight hours and so forth.
Why, and how? Well, by way of intermittent fasting impact in the expression of these various clock genes. And because the clock genes impact the mucosal lining, the mucus lining of the gut, it appears that intermittent fasting can reduce the amount of so called, lactobacillus, that's present in the gut.
Lactose bacillus is when in high levels is correlated with a number of different, metabolic disorders. At the same time time restricted feeding seems to enhance the proliferation of some of the gut microbiota like isil of actor. And some of the other ones that promote healthy mucosal lining and that promote better overall
intestinal function. So,
these are Pathways that have now been established, and it appears that intermittent fasting isn't just modulating these processes, but is actually
having
In a direct effect on the mucosal lining in a way that favors a healthier gut microbiome, so it should come as no surprise, that many people who experience gut issues benefit from restricting their feeding window to eight hours or so per every 24-hour period.
The other very exciting finding about intermittent fasting is one of the major health issues. These days is the proliferation of so-called
non-alcoholic fatty liver disease,
30 years or
so, non-alcoholic fatty liver disease was exceedingly rare to see in the clinic.
Except in Alcoholics,
fatty deposits in the liver are
bad. It is essentially liver disease,
nowadays, children and adults are
showing up with non-alcoholic fatty liver disease. Some of these people are obese, others are not, but it's a serious health concern and it's growing in numbers. All the time, a
recent study that was published in cell reports medicine, just a couple weeks ago tested the hypothesis whether or not the gut microbiome or so-called.
Brown
fat tissue is impacting The
Liver Health and in particular
non-alcoholic fatty liver disease, the
short, take away from the study. Is that contrary to what was previously, thought the gut microbiome. While very important for a number of other
processes in the body,
doesn't seem to be
related to this non-alcoholic fatty liver disease. This is surprising to people are should be to those of you that have been following the gut microbiome literature. However,
Brown fat, which is a healthy
fat that
Have between our two scapulae and in our upper neck. It doesn't tend to be blubbery type fat pads, but it's it's deep to the skin. But creates a thermogenic effect in the body.
That is helpful for reducing the amount of other fat. The type of fat that
we're typically used to thinking about and talking about white fat and pink fat, that's subcutaneous, fat around the abdomen and so
forth.
Brown fat seems to
have a direct correlation with the lack of non-alcoholic fatty
liver disease. What this study showed, was that in people that have diminished concentrations of brown fat.
There is a
higher
probability of having non-alcoholic fatty liver disease. Now, the good news is brown, fat stores can be increased. And again, this isn't going to create blubber of brown fat. This is going to create increase thermogenesis and actually make people
leaner and
brown fat has a number of other important positive.
X.
Now this is interesting because cold
exposure
of anywhere from one to three minutes,
two or four times per week, or maybe even 10 minutes,
two to four times per week, can increase Brown fat stores. Also, time restricted feeding has now been tied to
the density of brown fat store. So, time restricted. Feeding
also seems to positively
increase Brown fat stores probably, because of the way, the brown fat stores relate to epinephrine, and adrenaline, which tend to go up when we're fasted.
What does this all mean? This means
Ins for sake of Liver Health and for sake of reducing, or may be preventing, or even potentially,
when underline potentially reversing non-alcoholic fatty liver disease time, restricted feeding also appears to be beneficial many people out. There are interested in optimizing their hormones. And as we mentioned earlier, insulin is a hormone and time, restricted feeding
seems to have very positive effects on overall, insulin profiles and so forth. But anytime you mentioned hormones,
people immediately seem
Leap to the sex store at hormones testosterone and estrogen because
indeed they have powerful
effects both in the short term and the long term in terms of our mental and physical health and performance.
There's at least one study that's explored the effects of time. Restricted eating on performance athletic performance immune function and body composition. So was a study by morrow at all that was performed on Elite cyclist. So I want to point that out. It was a randomized control trial.
But what's really nice about this study is that it explored a number of different hormonal parameters in people that were using time
restricted eating, or that had a more extended eating window
and they tracked, everything very carefully and the amount of food. They were eating was actually pretty considerable 4800 calories. So that's a lot of calories. But then, again, they were very active. And they measured a number of
different things related to vo2max Etc.
Performance and overall performance.
At what they did cycling is
not the point that I want to emphasize here. Although there were some positive
effects on their performance related to
time, restricted eating the point. I want to talk about relates to things that presumably relate to most everybody, which are the effects on things, like
glucose thyroid hormone, testosterone, sex
hormone-binding globulin, which can bind up testosterone and prevent the so-called.
Reform of testosterone, which is the one that has most of the actions in the brain and body. And the major takeaway from this study was that time restricted feeding of the same amount of calories as the so-called control
condition. Okay, same calories, but either
compact throughout the 24 hour cycle to an 8 Hour, feeding window or allowing them to eat over a larger feeding window did lead to significant decreases in free testosterone. And I think a number of people will
Raise their eyebrows to that and think, oh, well, then maybe time restricted feeding is not for me.
There are a number of important considerations. Of course. One is while they decrease in free testosterone was significant. It's
also going to depend on where people start out. So if somebody has already low or modest levels of testosterone and it drops by 10 or 20% that could lead them into a state of poor performance in well-being. Whereas if somebody has higher testosterone a decrease won't
necessarily do that. So it's important to take that into consideration.
This is why I'm always such a fan of people doing their blood work and knowing what's going on under the hood for them. A very interesting change in hormonal profile, was cortisol so-called stress hormone
cortisol, of course, is also naturally released early in the day, in a healthy way to wake you up and promote alertness, but you don't want it's levels to be too high or to have Peaks and cortisol late in the day. It's actually correlated with depression and a number of other untoward
things.
I would have thought that by restricting a feeding window to a particular time each day that these hard training cyclists would have undergone increases in serum cortisol. And in fact, the opposite was true. They had significant reductions in serum cortisol as a consequence of time. Restricted feeding. I should mention there were significant reductions in
serum. Cortisol also in the control group, but not to the same extent and the two groups did
differ significantly from one another.
Now, this is important because
If you just look at one hormone testosterone, you'd say, Okay, based on these data time restricted feeding is reducing testosterone levels significantly, even though the number of calories is quite high and is held constant across the study, but in fact because cortisol is lower. It may mean that the effects of testosterone,
or the reduction in testosterone is offset, and that's
because cortisol and testosterone, or always in this
somewhat of a dance. In terms of cortisol inhibiting, the effects of testosterone largely and vice.
So so it is interesting and important to look at the total gallery of hormones. And they did, look at a number of hormones. They looked at other inflammatory markers. Those were not increased. That's not surprising. If you remember back to the 2012 Sachin Panda,
study this early pioneering study on time, restricted feeding. They saw reductions in stress hormones and in inflammatory markers in time, restricted feeding, mice. And here this also seems to be the case in humans. So, the takeaway
is
for sake of Hormone Health time, restricted feeding is compatible with
quality Hormone Health, even in high-performing athletes based on everything we know and that we've discussed. I would not suggest that people restrict their feeding window to less than 8 hours, especially if they're training hard on a regular basis,
and
it's not just athletes, that should pay attention to this. When we are working very hard when we are psychologically stressed, when we are studying for exams, or we are in conflict with
Buddy on a regular
basis that creates a stress in the body, that's very similar to that of physical training. The body and brain, don't distinguish between
physical stress and mental stress. It's all nervous system. Remember that? It's just cortisol and adrenaline. There's no
special hormone
just for physical stress versus psychological
stress. So again in thinking about what sort of feeding window will be right for you. We arrive
back at this eight hour
time bin. That seems more or less
flexible for most conditions even high.
Forming Elite athletes. And I would say, just by logical
extension, even for
people that have a lot of stress in their life, and I
personally wouldn't suggest that people who have a lot of stress in their life, where the potential for stress in their life.
Shorten their feeding window much shorter than eight hours because then you would expect that you would start to increase some of the inflammatory markers. You would increase the stress hormones
and you would be decreasing things like testosterone and
estrogen and some of the sex steroid hormones. So again, it's all about
Context and the eight-hour window,
it isn't wholly, but seems to be a really useful guide to
extract the great
health benefits of which there are many in of which we've discussed from intermittent fasting, time restricted, feeding. And yet that it could still be compatible with decent, social schedules and for maintaining Hormone Health in keeping with this for
women that are trying to maintain
ovulatory Cycles or for couples that are trying to get
pregnant.
I think it's also important to not create a feeding window that's too short. The relationship between feeding and body, fat stores and glucose and leptin, and hormones is a well-established one. And we can
summarize it very easily here. Although I've done several episodes related to this previously on optimizing Hormone Health,
but basically we undergo puberty, when there's enough food, and there's enough body fat, that the body fat sends a signal to the brain called leptin.
Hormone that comes from body, fat signals to the brain to turn on puberty that's puberty. But even as adults for women that are menstruating, there needs to be sufficient leptin signaling to the brain in order to maintain ovulation because of the way that the brain communicates with the pituitary in the ovaries. Similarly for men fasting or extreme exercise plus
fasting. We now know reduces testosterone.
It's impacts are not exactly clear. However, if you reduce food intake, either in total calories or induration
too much, you will suffer a drop in sperm, counts, fertility, will drop. And this makes sense. The body is communicating to the brain, whether or not conditions are
sufficient in the body to reproduce and to presumably. And hopefully support the health and well-being of those Offspring.
So there's a logical link between body fat and eating and how much food is available.
To you and how long it's available to you
and the signals in the brain that allow for Reproductive success.
There are some data that pointed differences in the effects of intermittent fasting for males versus females. Those data. Right now, only come from mice. That study was published by Sachin Panda, recently. We still await the studies in humans. Some people do not do
well on intermittent fasting, either in terms of mood or
Hormone Health, and so everyone needs to determine for themselves, whether or not having a Time restricted.
Eating window is good for them. How long that time restricted feeding window should be? I think eight hours is
kind of a nice minimum to adhere to based on everything that we've covered today.
And for some people time restricted feeding is not going to be
compatible with Hormone Health,
for them, for them eating more meals spread throughout the day. Presumably smaller meals, same caloric intake is going to be more beneficial for their hormones. This is something that is going to be individual and is going to have to be determined
on an individual basis. However, if you're going to try
I time, restricted feeding. I do want to remind you that taking a period of three to seven or ideally 10 days to transition into it. Not just going
flipping from eating two, three meals a day that span from 6 a.m. To 10 p.m. And suddenly going to an 8 Hour, feeding window, but rather winnowing down that feeding window
about an hour or so. Per day is
going to allow the hormone systems of your body, including leptin. The hypocretin orexin system, which are systems within the body that signal to the brain that food is about to come allowing those systems to
just so that you're not overwhelmingly
hungry irritable and you're not throwing your whole hormone system out of whack. I keep coming back to this 8 Hour feeding window and I want to provide a little more
basis for it and just to encourage that it's not completely
arbitrary.
The lengthy review that I mentioned earlier features a number
of studies that have used this 8 Hour feeding
window.
But there's a particular study that I'd like to highlight mainly because I don't expect people to delve into the full reference list of the other review. And this is a study that was carried out between Sachin pandas lab and Krista varieties lab. So this is a collaboration. The study was carried out in humans and is entitled effects of eight hour time restricted feeding on body weight and metabolic disease, risk factors, in obese, adults, excuse me, and this study essentially showed. I'll just read the conclusions.
That an eight hour, timer started, feeding produces a mild, caloric, restriction, and weight loss without calorie counting. So that's key, right? These people aren't calorie counting somehow just by adhering to an eight-hour window. They are taking in fewer calories than their burning off and
clinically it reduced blood pressure.
So I mentioned the study not because there aren't
many others involving The 8 Hour feeding window also in humans, but because the a towel
Are feeding window has been tested in obese, adults, and not obese, adults, and there are even
a few studies in children. So, this eight-hour window seems to be a really good rule of thumb and a kind of anchor around, which we can each, think
about incorporating time, restricted feeding. There are of course other
patterns of feeding. And while some people have engaged
in longer fasts of 24 hours, 36 hours or more alternate day fasting, meaning eat.
One day, not eating the next day or in some cases, eating one day and eating very few calories, 500 or 600 calories. The next day has been tested. A
few Studies have also looked at eating a sort of
Maintenance level of calories for five days and then taking two days and fast and clear through, or eating very few calories, you know, 300 or 500 calories. In fact, there's a sort of a community online of people that are exploring longer fast for sake of trying to offset dementia. A reverse effects of
Shh, thus far, at least in my awareness. There isn't any quality,
clinical peer-reviewed study on that yet, for sake of dementia. Although I await those studies, and if anyone's aware of them, please send me a link in the comments,
but alternate day fasting has gotten the so-called safe bill of health. This has been written up, meaning, that people didn't suffer bone loss. They didn't suffer any major detrimental effects. It does seem that it can create.
Significant weight loss and can help with obese individuals that it can reduce resting blood glucose.
And every other day fasting, in many cases can produce more rapid
effects on weight loss and reductions in blood glucose than time, restricted feeding.
However, every other day type fasting for most people is not going to be
feasible. They're just not going to be able to do that for a long period of time. And what hasn't really been done is the follow-up to see whether or not people who do every other day fasting or five days of
eating followed by two days of fasting whether or not that leads to a rebound in weight gain, whether or not that leads to a rebound in blood glucose Etc.
So for now, The 8 Hour feeding
window and time restricted feeding
seems to be the most tested supported in animal studies and in human studies and the one around which I think most people
should Orient if they're considering getting into time, restricted feeding. It's also sort
of hard to imagine how one could
include a significant exercise.
Or work schedule on every other day fasting. Remember in
any study people are often being compensated or at least are
incentivized in some way to adhere to the study. This
is one of the major issues that I have with any study that says
that three or four different diets are essentially equal in terms of their ability to produce weight loss. Adherence is very different in the outside world where you don't have a researcher monitoring you where you're not logging all your food. Most people don't do that consistently and we can take a little bit of
a neuroscience perspective on this to try and arrive at what, the best kind of
organization of eating plan, or if we wanted to call it a diet, we could would be for you.
Many people find it easier to just not
eat for certain periods of each 24-hour cycle, then to
eat smaller portions portion. Control is
very hard for some people for
other people. It's manageable, but people like me, I don't eat half
the croissant. I don't think it's a real thing. It's not a, it's not available.
To me, I should say. Now. Of course, I could eat just half a
croissant, but I noticed that when I eat the croissant because they're so delicious, that it creates a rise in blood glucose arise in the other hormones and chemicals that are associated with ingesting,
delicious, highly, palatable food
and it's actually a lot of work for me to just eat half the croissant. There's something that's much more thoroughly satisfying about eating
the entire croissant. And
actually there's something that's somewhat satisfying about not eating the grass.
Santa at all and
just knowing that later, I can eat the whole
croissant. Now, that's me other people, find that they don't have any trouble with portion control that for them just eating small bits of food throughout the day, is what sets them in the,
right? Psychological and physical state, for sake of work, etc.
And I mentioned work and mental focus because one of the
aspects of fasting that have drawn, a lot of people to time, restricted, feeding and
fasting is the clarity of
mind that people get. When first of all, they don't have to think about when they're
To eat because they know when they're eating window begins.
They also don't have to think about regulating their behavior because they already know when they're going
to eat and when they're not going to eat, whereas when you're restricting portions, you actually have to make decisions all the while, you know, and I think I like many people decide. Well, you know, is that exactly half where could I have like
another rung on the croissant, this kind of thing? I don't negotiate with food. That's why I like a Time. Restricted feeding window. I know
I'm going to eat for in my case. I use a 10 hour feeding window or so.
And I'll eat the whole croissant. I just don't have to think about it.
Now, the food choices that you make inside of that, feeding
window are of course, also going to be very important. Certain foods will increase blood glucose such that you're going to get
hungrier and hungrier, others will maintain lower, blood,
glucose and will allow you to be more controlled in the foods that you pursue.
Those are all individual considerations that are deserving of their own entire episode. But I do want to point
out that the advantage of time restricted feeding is that it involves a lot of the
Session making in the brain. The so-called go/no-go
circuitry's of our basal ganglia. If you want to know this areas that control
them, anytime. We have to restrict a behavior that's
called a no-go.
Anytime we engage in a behavior.
That's a go, no-go
behaviors, require a lot of what's called top-down
control and it's very metabolically demanding. And so time, restricted, feeding allows you to depart
from the whole. No, go go negotiation. That you have to undergo when you have
to restrict portions. And so I think this is
is a reason why many people have gravitated towards time restricted feeding and why for
people that don't want to have to think
about all that. It's just very straightforward. One
of the more hot-button
issues out there is whether or not given
equal amounts of caloric intake and equal amounts of activity and equal amounts of nutrients etcetera, whether or not restricting food to a
particular window biases,
more weight loss toward fat loss versus
loss of other tissues.
Of course, when we lose weight, we can lose that from any number of different storage sites within the body, muscle water
glycogen.
Or fat. Now. This is such a
hot-button issue that I almost don't want to get into it, but I'm going to get into it anyway because there are data
that are very interesting.
This is covered in the review that I mentioned earlier.
That describes how if people follow a Time restricted feeding schedule for long periods of time. So 60 days or longer, there are some metabolic changes in the way
that people metabolize
energy that do seem to shift the system.
Third more fat loss relative to burning of other tissues when, in a state of caloric restriction. And I want to say when in a state of caloric restriction because there's really no way to cheat the system. There's no way that you can
ingest far more calories than you burn or excrete when I say
excrete, you know, I certainly don't suggest this but they're you know bulimics and other people that have Eating
Disorders will use laxatives that a way to eliminate food quickly from their system. So it can be converted into fat or other forms of
energy. That's a very
In that case. It's a pathological situation. But in general calories in versus calories out. As I mentioned earlier, is this kind of foundational element, but in states of caloric restriction, meaning sub maintenance intake.
Time restricted feeding does seem to buy us more of the energy burned to compensate for that deficit from fat. And the way it accomplishes. It is very interesting. It turns out that it drives more fat loss by way of increasing at hepatic
lipase. This is something called el IPC. Hepatic
means of the liver and lipase, which any time you hear a sec is means it's an enzyme. So it seems to increase hepatic lipase. So it increases the
Zayn. That metabolizes fat for lipolysis in energy production and reduces something called side x EI DEC, which is a lipid droplet Associated and lipolysis inhibitor. Now that's a mouthful, no pun intended. But what sidek really is this lipid droplet Associated molecule is it can inhibit lipolysis? So extended periods of time, restricted feeding, meaning
ate our feet?
Ding window or 10 hour, feeding window, that's obeyed
for several months or more seems to allow the system to shift toward burning more fat or rather using a higher percentage of fat when in a caloric deficit.
Now, I doubt that. This is going to resolve the truly barbed wire, almost hairball ridiculous. Online. Debates
about whether or not time
restricted feeding is better than another feeding schedule. Look, I don't think any particular feeding schedule is Holy.
If you are sub caloric, meaning fewer calories, burned than calories ingested, you're going to lose weight. But the data seem to point to the fact that if you do time restricted feeding for a fairly long duration of time, and you maintain that that you are increasing these lipases that increase lipolysis energy, use from fat and you are decreasing, the lipid droplet Associated lipolysis Inhibitors. So it's both a, you're removing the brake and you're pressing on the accelerator of fat loss. I
That this logically points to a case in which using time restricted feeding with a sub, caloric intake, seems to be at least, to my mind, the most scientifically
supported way to ensure that a significant portion of the weight. That one loses is from body fat
stores. Any discussion about fasting would be incomplete without a discussion about what does and does not break a fast. However, there is no black and white
answer.
To that
question. And you should immediately understand why? It's because eating and not eating are not equivalent to fed and fasted. It depends on
when you ate how much you ate
and
where you are in your circadian cycle.
We can actually arrive at a simple
answer to whether or not something breaks the fast or not. Now, the technical way to go about this would be to wear a continuous glucose monitor and to ingest little
bits of food of different.
Or large amounts of food of different kinds and measure blood glucose. Because ultimately
blood glucose is the readout of whether or not your system is in a fed or fasted State. There are other parameters to of course, but that's the dominant one
in so far as the scientific literature says,
Drinking water will not break your fast.
Drinking tea will not break your fast. Drinking coffee provided. It is black coffee will not break your
fast. Ingesting caffeine in pill form, will not break your fast. There are other things that won't break your fast. For instance, eating one peanut when deep, in a fasted state will not break your fast. Eating a
whole handful of peanuts, might not even break your fast, if you are in a very low
glucose State, however, if you just finished a meal, that included carbohydrates, or it was a very
Large meal of any kind an hour ago.
Yes, indeed. Eating one peanut Could Break Your fast so it's all
contextual. That's what's really important to understand.
Unless you're going to wear a continuous glucose monitor. And unless you are going to wear a continuous glucose monitor and set an absolute numerical threshold
for what it is to break your fast.
I think there are some simple rules that we can follow. First of all, anything that involves
Sugar in particular, simple sugars can potentially break your fast, and there's actually a study on this, which shows that, if people, ingest, even one, one gram of sugar post-dinner. If they had a full meal for dinner, that can actually disrupt the expression of some of the Circadian genes related to fasting
and to sleep and sleep related fasting. Now, that's pretty extreme.
It's almost kind of scary to think about but that's how sensitive our system is if we already
Have somewhat elevated blood glucose from a meal that we ate an hour or
so ago. Whereas if we have run for an hour or trained hard high intensity training and we haven't quite reached the beginning of our so-called feeding window will eating a small amount of food. Take us out of that fast. Well, depends on what the food is, if it's mostly fat, probably not a number of people out there, nowadays, talk about so-called fat fasting, fat fasting is
Way too kind of Regal past the stringency of either eating or
not eating as a black-and-white rule for feeding window versus non feeding window. So some people
will ingest medium chain triglycerides,
so-called MCTS or people will ingest
fats only until their official feeding window begins. So these are sort of how the negotiations that people carry out tend to go. But a fat of course, won't increase blood
glucose and Insulin, as much as carbohydrates, will
protein will.
Have sort of in an intermediate
effect. And as I mentioned earlier, ingesting carbohydrates, with some fat will tend to blunt the rising glucose and will extend the duration over which glucose is released.
So we really can't say food X or beverage X breaks a fast. However, at the extremes we can say that. For instance, if you drink a can of soda pop,
Unless you just ran an ultramarathon. You're breaking your fast. Okay, eat a piece of pizza. You're
breaking your fast. If you eat purely
fats, maybe probably not. If you've been fasting for five hours or more
strictly fasting for five hours or more so you can start to see where
there's a lot of wiggle room and it's very contextual. And this is why any post that you see or any information
that you see that something does or does not break your fast. It doesn't place it in the
context of when the last time
you ate.
And what you ate
and your activity and
your time within the circadian clock schedule of 24 hours. It's a sort of meaningless discussion. So in general, I think
what's really useful, if you're not going to wear a continuous, glucose monitor is to try and be fairly strict about when you initiate your feeding window. And when you stop your feeding window,
and as time evolves, and you establish a more regular routine of eating certain kinds of foods and not others that are right for you because, as I've emphasized before, on this podcast and I will continue to emphasize key,
I do works great for
some people. Vegetarian Quito works great. For some people. Carnivore diet works, great for other people.
Some people are omnivores. Some people are carnivores. Some people are vegan. All of that is great and fine by me. Everyone has to establish. What's right for them
today? We've really bypassed the discussion about foods of a particular origin or type animal-based or plant-based.
But all the same rules apply within this thing
that we call, intermittent fasting, or time restricted feeding. So what?
Fast will depend and what you want to eat, or what you are
willing to eat. That's a totally separate
manner from when you eat. But as we've established, when you eat is vitally important,
some of you are probably wondering whether or not artificial sweeteners or non-artificial plant-based sweeteners, like
Stevia, break a fast.
This will vary somewhat and I have to say the data on this are somewhat mixed. There is evidence that when people ingest artificial sweeteners that it can create a transient increase in blood glucose, followed by a transient
decrease in blood glucose below
Baseline. This is thought to explain the increase in hunger caused by ingestion of things like
aspartame and Sucralose and things of that sort.
There are not a lot of
good studies exploring. The plant
based.
Sugar sweeteners, things
like Stevia, even things like monk fruit, which is a separate category unto itself. There aren't a lot of
studies on this. I think most people need to establish this for themselves. The best way, of course, would be to wear a continuous glucose monitor
to go into a fasted state of either one hour or two hours or maybe you've been fasting all night and then ingest Stevia and whatever form you want or coffee and whatever form you want with sucralose or aspartame
Etc. Setting aside, the discussion about the effects of these things on the gut
microbiome, which is
A different topic entirely. I
think it's fair to say that in moderation. The plant-based non-sugar sweeteners, like Stevia. In particular, Stevia seem to have a minimal
impact on overall blood glucose. When considered over a fairly large time, bin
aspartame and Sucralose saccharin. I think we can say more or less the same. But as soon as you get into a discussion about those, you also have to get into a discussion about some of the evidence
published in nature and other excellent
journals. Now,
Pointing to the fact that when consumed in excess not when consumed in
moderation, but when consumed in excess that those might have some detrimental effects on the gut microbiome,
so do artificial sweeteners, break a
fast, depends on the amount, depends on the
type and in general, I think you're probably
okay provided that you're not indulging in them, too often.
However, some people just by virtue of tasting, something
sweet, feel, a spike in their appetite. That makes it harder for them to adhere to the feeding window.
And so this is why you can imagine that a
really well controlled study on this would
be very hard to carry out and I'm not really sure that it's worth our tax dollars to actually
design and carry out a study like that because there would be so much individual variation in terms of discipline in that hearing to the feeding window whether or not people experienced
increases and drops in blood glucose how that impacts them whether or not they're
exercising. It just becomes an
infinite variable space as we say in experimental science. So you really have to determine that for you, but I don't think that
We can fairly say that artificial sweeteners break a fast. I think that would be incorrect to say,
earlier. We were talking about glucose,
disposal agents, both
behavioral
and compound base, things like metformin, and berberine. And in fact,
cinnamon is even a mild glucose
disposal agent. It can actually reduce blood glucose
lemon and lime
juice, believe it or not can lower blood
glucose. You may have experienced this before of eating something very, very
sweet and almost feeling kind of overwhelmed and out of poisoned by How
Sweet It Is.
See, if you're not accustomed to eating a lot of sugary things. One, quick remedy for that is actually
a half lime or
1/2 lemon squeezed into juice and drinking that just by virtue of the taste, and by virtue of the fact that it will reduce blood glucose. You'll notice that that
affect almost immediately disappears.
That's not magic. That's the effects of acidity on blood glucose levels. So there are a number of things that can adjust
Blood glucose, they're not necessarily disposal agents. They're not sweeping
it out of the bloodstream in the same way that berberine and Metformin would or that high intensity exercise at the appropriate times of day would. But
there is one particular thing that one can ingest, that can help manage psychologically and performance-wise through the fasting portion
of the intermittent fasting and get you to your feeding window. And
that's salt. I've talked a little bit about this on the podcast.
Ask before but because neurons use salt sodium and potassium and magnesium. The so-called electrolytes in order to perform their magic
of chemical and electrical signaling. Everything. You do depends on chemical and electrical signaling and all that chemical and electrical
signaling requires electrolytes in some form or another neurons run on the passage of ions,
like sodium in and
out of their cell. Membranes
are should say across their cell, membranes to be accurate.
Many people find that the kind of lightheadedness the shakiness that's accustomed with having slightly low blood sugar
can be offset by taking 1/2
teaspoon or so of sea salt, or even just a tiny pinch of salt and putting into some water and drinking it.
Some people find because of the
glucose lowering effects of acidity that if they're feeling kind of shaky and not. Well, and they put some lemon juice into water and drink that it drops their blood glucose further.
So, there's a common practice nowadays, that's discussed
on the internet of waking up, drinking some water with some lime or lemon juice in it with a little
pinch of salt. I think that little pinch of salt is a good idea. What is it doing? How is it offsetting all this? Well, salt water actually has a mild effect as a glucose disposal.
But it has a stabilizing effect
on blood volume and so because sodium brings with it water and the so-called osmolarity of your blood and your body depends on the salt levels in your blood and brain and body.
Many people find that if they're feeling shaky. They're feeling light-headed. They can't concentrate. They think they need sugar or food, but what will actually Remedy, that
is some salt and I know a number of people that have Incorporated this practice and have written to me and saying, oh, you know, I just take a little bit of salt and some
I'm water, they may or may not include the lemon or lime juice. They immediately feel better and find that. It's actually quite straightforward to get out to that to wait until the feeding window kicks
in. This is especially true for people that are using caffeine because when you ingest caffeine, you actually excrete a lot of water as a diuretic effect. And with that water goes
salt, so it actually causes you to excrete sodium. Now the
role of sodium in blood pressure and hypertension is, you know, quite controversial Science magazine. One of
Premier scientific journals out there at a special issue all about salt.
Some years ago, talking about the research around
hypertension indeed people with chronic hypertension or high blood pressure or very high blood pressure.
In particular, should be wary of ingesting too much sodium, but for most people
ingesting sodium provided. They drink enough water and they
don't have chronic hypertension or high. Blood pressure
is actually beneficial. That doesn't mean you should be drinking seawater doesn't mean
you should be over indulging insult.
But many people find that they can
manage their mental and physical state, and even
feel really terrific real Clarity of
mind and really enjoy their fast when they're ingesting, sufficient salt and all it requires really is a small pinch of salt, ideally Himalayan or sea salt if you want to get fancy about it, but table salt would be fine and just
drinking that in some water. Maybe with lemon or lime juice to
offset the taste a little bit. Can
really stabilized ones Jitters and can stabilize the mind and you
Also notice can offset that churning and
yearning and appetite. Where you can't imagine going another five minutes before eating something. Suddenly you feel, okay, and that has to do with a lot of the effects of blood volume caused by ingesting salt in the appropriate amounts. In other words.
Sometimes you think you need food. But what you really need
is salt and salt can make you feel better immediately.
I'd like to mention two. Excellent,
zero cost resources. If you're going to explore time, restricted feeding, or maybe if you already are doing time.
Restricted,
feeding. I have no affiliation to either of these, the first is the website that I mentioned before my circadian clock, which is the website hosted by Sachin Panda and colleagues. There are a lot of
resources there where you can log your food intake. Get information about time, restricted feeding, all the science. The ongoing studies Etc. The other is the so-called zero app. That makes it very easy to
Mark when you're beginning your feeding window and when you're ending your feeding window and in so doing marking when you are beginning, your fast and ending your fast or at least initiating the beginning of the unfed state as we could more accurately call it. It's a
terrific app. I've used it from time to time. I don't tend to use it in an ongoing basis because I'm just sort of used to eating at a particular time of day now, but any time I've shifted that window
for instance, a few weeks ago. I started moving that protein intake in my entire feeding.
Earlier in the day and because that takes some
attention on my part because I'm not used to doing that. I've been using the zero app and I like it quite a lot. It logs your progress and it gives you averages and you can see how many other people are fasting. Again. Totally zero
cost. I actually don't know who owns that app. But I think they've done an
excellent job. The interface is really terrific. And as far as I know it's available for Apple and Android, but it's at least available for Apple phones, which is the type of phone. I happen to have. So
check those out my circadian clock. You just put that into Google.
You'll find it and the
zero app. Both excellent, zero cost resources
in a moment. I'd like to review the parameters
of a ideal feeding schedule for you and give you the variables that you can plug into your lifestyle and your preferences. There are a
couple of things that I would Place into the category of frequently Asked somewhat odd, but still worthy of discussion. For instance, people have asked will brushing your teeth with toothpaste, break your fast.
I think unless you're swallowing the toothpaste know. Now, if you really want to run out and get a continuous glucose monitor and brush your teeth and you
can evaluate that, but no
people have asked will 1/2 glass of wine
after dinner a couple hours after dinner, break your fast.
Absolutely, it absolutely will. And
it's been demonstrated to do that based on the one gram of sugar, kind of eerie or scary effect that I talked about before, scary and area because it just seems like one gram of sugar. How could it?
Do that. But these are metabolic processes and they are very sensitive post-meal. A
few months back. I did an experiment, wearing a continuous glucose monitor,
and I got a
surprise when I discovered that going into a sauna increases, my blood glucose quite a bit actually spikes it, as high as a meal and then it
tends to drop back down to baseline or even slightly below Baseline afterwards.
When I talk to people about this.
Somebody said, oh, it's got to be that the
continuous glucose monitor was getting disrupted by the
heat in the sauna. That's actually not the case. Turns out that when you go in a sauna because you dehydrate your losing
water. I wasn't drinking water and you're dropping a lot of water, the concentration of sugar in your blood actually goes up and I actually put these data out in a social media post on
Twitter
and people were kind of shocked to see how much a song I can spike your blood glucose.
Now, I do practice
time, restricted feeding, intermittent fasting. I'm not super strict about it. I use a kind of eight to ten hour, ish window, either, early in the day or late in the day.
I saw this effect of the sauna, personally, the psychological and physical health effects of the sauna are valuable enough to me,
that I continue to use it. I'd just not concerned about this increase in blood glucose to the extent that I'm going to eliminate sauna. I like to use the sauna three or four times a week before.
Sleep. So I'll use an hour or two before sleep.
And yes, indeed. It
creates this big spike in blood glucose that then drops based on change in the concentration of blood sugar.
I'm just not going to worry about it. Now if you're
concerned about blood glucose spikes, then you might be worried about it. But in
my case, it was one of those things where it was interesting and it
was worthy of discussion. I thought because it was somewhat surprising to me. Although it makes perfect sense, why this
would be the case, but at the end of the
day, literally it just makes sense for me to get in the sauna. Okay. So now you've heard
A
lot of science, you've heard a lot of examples, even a few anecdotes, and
let's come up with the ideal intermittent, fasting AKA time,
restricted feeding schedule for you. And when I say ideal, I mean, what are the variables that are negotiable? What are the ones that are non-negotiable? What is ideal for, you will
depend on the context of your life and what you are willing to do consistently, so
first of all, we established based on the discussion with Sachin who is
truly the premier World expert in this area, who knows the animal and human scientific literature better than anybody has written this incredible review and for whom I consulted
that
You do not want to ingest food for at
least, I want to emphasize at least 60
Minutes post waking up.
Second, you want to avoid ingesting, any food of any kind, even one gram of sugar. Remember? This is the ideal
one. Gram of sugar, even would be too much for the two to three hours prior to bedtime.
He also mentioned ideally, you are spending eight hours in bed. I
didn't tell you that earlier. I save that for now,
but
ideally you are sleeping that entire eight hours,
but simply by being in bed for that. Eight hours
and avoiding.
After waking for an hour. And before bed,
for 2 to 3 hours, you're starting to build out the duration of this fasted
period.
Remember that the sleep-related fasting is particularly important for the
health benefits of time. Restricted feeding. Again, the sleep-related fasting is especially important because of all the seller repair processes that occur in the liver, in the gut, in the microbiome, in the brain, all over the body and because of the way that that coordinates, the expression of the clock genes that are then going to Wick out and have many other positive effects on health.
Cluding weight and fat loss. But in addition to that Liver Health Etc.
An 8 Hour feeding window
as a Target seems to be
the best Target feeding window at least by my read of the literature. And in discussing it with chud such in
shorter feeding Windows of four to six hours, tend to lead to overeating and potentially increases in wait.
One meal per day, type eating do not seem to do that. But those are special cases in that most
people can't adhere to a one meal per day type schedule, at least not on a regular basis and it's not very compatible with most social schedules. Although
some people may be able to adhere to that in a straightforward way, but there aren't any
robust studies exploring the advantages of one meal per day. So if you feel there are advantages of one meal per day for
you.
As opposed to an 8 Hour feeding window will, then by all means use a one meal per day
approach or use a four to six hour,
feeding window and just make sure you don't over eat in that
window.
Remember that most people tend
to not adhere to The 8 Hour feeding window. They say, 8 hours, but they tend to eat outside of they have eight hours a little bit on each side. So if your goal is a 10-hour feeding window, you might want to set it to nine hours or eight hours. If your goal is six hours, you might want to set it to seven or eight hours. And this is simply based martians. They simply this is based on thousands. If not tens of thousands of human subject data.
It's that such an and colleagues have collected.
Regular placement of the eating window.
Or feeding window, every 24 hours is important. You don't have to be absolutely rigid and erotic about this but you don't want it sliding around on the weekend so that it's starting two hours later and ending 2 hours later. A couple days a week because then, you start to
offset many of the
positive health effects that have been demonstrated for time restricted feeding.
Remember if you eat your food within a certain feeding window, but that feeding window shifts by a couple hours. It is effectively like jet lagging your system. It is effectively like traveling a couple times owns over eating there for a few days and coming back. When in fact, you're not traveling. That's because of the way that food, adjust the circadian clock genes. Now, you can offset some of that through the use of light and I've talked extensively about,
How to use light and previous podcast. But again, early morning and all day bright light exposure, as safely as you can ideally from sunlight not through window Etc, avoiding bright light in the middle of the night. Extremely important for mood offsetting metabolic dysfunction, Etc.
Not incidentally such ins early work. Was he was one of the three
Co discovers of the cells in the eye, the so-called melanopsin cells that set the central circadian clock. So he was a Pioneer in that field which led him to
be a Pioneer in this field and so on.
When should that eight-hour
window, be placed within each 24-hour cycle? Well, let's talk about ideal
ideal. If you really want to maximize all the health benefits of time, restricted feeding. You need to extend the fast around, sleep on both sides. You would place it smack-dab in the middle of the day. It would be a schedule in which you started eating, for
instance at 10 a.m. And you stopped eating at
Six pm an absolutely Dreadful schedule for anyone that wants to have some semblance of a normal life. In my
opinion. It's not really compatible with most schedules. Although some people might be able to do it, maybe you and your family or your friends. You're,
you know, you're eating a late breakfast or a and then you're having a latish lunch around 2 p.m. And then you have dinner at 6:00
and then assuming that you go to bed around 9:30 or 10:00 p.m.
That is going to extract.
The maximum amount of weight related body fat related,
metabolic Factor related aspects of time restricted
feeding. Some people tend to fall into a category where they do best placing that feeding window later in the
day and provided. It doesn't run too close to your sleep. Remember you need a two or three-hour buffer before your sleep? Where you are not ingesting anything that's in order to extract the benefits of time,
restricted feeding. Well, then starting your feet.
Window at 12
p.m. And ending at 8, p.m.
Plus or minus half an hour or so,
day-to-day seems like a perfectly reasonable schedule for some people starting at 2 p.m. And ending at 10 p.m. Will be that schedule. Of course, you have to take into consideration when you exercise. If you exercise
for instance, I like to exercise early in the day if I
run or if I do some moderate or light, intensity exercise, regardless of what type of exercise it is. I have no trouble.
I'm waiting until my feeding window kicks in around noon or even 2 p.m., But if
I do high-intensity weight
training, for instance, early in the day, or if I run sprints and I do that at 7 a.m. Or 8 a.m. By 11 a.m. I'm very, very hungry. And it's hard for me to do other things. Concentrate, Etc. Now, I'm not neurotic about my feeding window as I mentioned before, I kind of let it expand and contract a bit around the 8 hour mark and feel perfectly free to do that to we're talking here in ideals. Not in.
Necessarily practicals. But other people find that they're very hungry. When they wake up early in the day. If you're one of these people or you're somebody who really is trying to emphasize hypertrophy
or maintenance of muscle, then it does seem that ingesting protein early in the day is beneficial, that it can be more readily converted into muscle tissue. And this has been demonstrated in at least one study. There's another study underway that's exploring this
further.
For people that are really,
really interested in hypertrophy and building muscle will then time restricted, feeding is usually not the way they go. I mean, let's be honest. There are many people out there who are eating for more meals per day and they're doing that from 7 a.m. Until 8 p.m. I realized that not everybody is overweight. There is an obesity crisis indeed, you know, the percentage of obesity and non-alcoholic fatty liver disease is just Cosmic through the roof at least in this country and in other countries as well. This country me in the US but other countries as well.
But there are, of course, people that are trying to gain weight, who don't want to lose weight, or who are trying to maximize physical performance, or hypertrophy or things of that
sort. And so of course, time restricted feeding for them might be as long as I'm
awake. I'm eating and I, you know, I tip my hat to those people and just say, you know provided you understand what you're doing and the burden that that places on some of the other processes in your body. If that's right for you then by all means, pursue that
Another thing that we can add to this summary or key points related to time restricted feeding is the use of glucose
disposal, agents and or behaviors.
If you find that you've eaten too close
to a period of time in which you would prefer to
be fasting. That's when a 30-minute brisk walk, or even modest, walk after
eating can be beneficial ingesting. Some lemon juice or lime juice can help lower blood glucose somewhat.
And then there are the things like metformin and berberine there. Even some supplements out there that combine things, like berberine cinnamon, which can lower blood glucose and things like chromium. And
Is that have a mild effect on blood glucose, but berberine and Metformin are very high. Potency glucose, disposal agents. And I mentioned earlier, why you would want to approach those with the appropriate level of caution, and figure out the dosages for you. And for some people, the dosages will be 0 milligrams is going to be ideal.
And then, of course, we discussed how making sure that you're ingesting enough fluids and
particular water and salt,
especially if you're using caffeine
in order to
Increase your levels of alertness regardless of where that caffeine Source comes from coffee to your otherwise that can cause the excretion of sodium and can lead to a kind of shakiness a light headedness and the
feelings of hunger that may or may
not be related to blood glucose. Some people genuinely need to eat. I certainly would not want to see people getting hypoglycemic to the point where it's dangerous. Certainly, if you are diabetic you and in fact, we're all people, you should consult with your physician when
Luring any major changes to diet or additions or subtractions of anything including supplementation, but for most
people maintaining relatively low too, modest blood glucose levels is going to be pretty healthy
and will allow all the positive effects of intermittent fasting to
occur. And when you find that reaching, that start to the
feeding window is challenging, that ingesting sodium can often stabilize your system mentally and
Ali and allow you to reach that window. Often painlessly.
And then, as a final Point, as I mentioned earlier, provided that they are consumed in low, no or modest amount. Artificial sweeteners, or plant-based non-sugar. Non-caloric sweetener
don't seem to really impact blood glucose to the extent. That it would quote, unquote, take you out of your
fast, but that like, fat
fasting is something that's going to be highly individual and that you're going to have to
Berman with for yourself and being
able to recognize when you're in a fast and when you're out of a fast
at a subjective level and not constantly having to measure your blood glucose, or do things of that sort
can be beneficial. And I think, if you watch for
the feelings associated with eating and post eating foods of different kinds and different amounts and you watch for the feelings associated with being fasted for long periods of time or short periods of time of having gotten sufficient sunlight of
Train hard or not trained hard earlier that day Etc.
You can do the most important thing, which is to start to learn to evaluate your own system to run simple. Safe experiments on your system in a way that allows you to really establish the ideal
nutrition schedule for you, whether it be time, restricted, feeding AKA intermittent fasting or some other nutritional plan.
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And send the supplement industry as a whole, is that the quality and amounts of supplements,
often varies tremendously.
Therefore, we've partnered with Thorn TH or any because Thorn has the absolute highest levels of stringency, with respect to the quality of ingredients and the amount of the ingredients matching. What's on the label. If you want to see what I take and get 20% off any of thorn supplements. You can go to Thorn thoi knee.com, the letter U / huberman, you'll see the list of supplements that
I take you can get 20% off those and if you enter the thorn site through that portal, you get 20% off. Anything that thorn makes. I know we covered a lot of information today. I hope you learned a lot about time, restricted feeding. I hope you learned a lot about metabolism and energy and health and how when you eat is as important as
what you eat and last, but certainly not least. Thank you for your interest in science.
