The Dr. Hyman Show - Why Fasting Isn’t A Fad: Discover The Surprising Health Benefits | Dr. Mark Hyman
Episode Date: November 8, 2024Fasting isn’t just about skipping meals—it's a powerful tool to improve your health when done right. In this episode of “The Doctor’s Farmacy,” I tackle the most common myths about fasting a...nd dive into the science behind how it impacts your metabolism, hormones, and overall well-being. You’ll learn how to navigate different fasting methods, from intermittent fasting to time-restricted eating, and discover how they can help you burn fat, preserve muscle, and even boost longevity. View Show Notes From This Episode Get Free Weekly Health Tips from Dr. Hyman Sign Up for Dr. Hyman’s Weekly Longevity Journal This episode is brought to you Mitopure, Rupa University, Big Bold Health, and AG1. Support essential mitochondrial health and save 10% on Mitopure. Visit TimelineNutrition.com/Drhyman and use code DRHYMAN10. Rupa University is hosting FREE classes and bootcamps for healthcare providers who want to learn more about Functional Medicine testing. Sign up at RupaUniversity.com. Big Bold Health is offering my listeners 30% off their first order of HTB Rejuvenate Superfood Head to Bigboldhealth.com and use code DrHyman30. Get your daily serving of vitamins, minerals, adaptogens, and more with AG1. Head to DrinkAG1.com/Hyman and get a year's worth of D3 and 10 Travel Packs for FREE with your first order.
Transcript
Discussion (0)
Coming up on this episode of The Doctor's Pharmacy.
You gotta start your first meal with protein.
Protein will help you live longer, be healthier.
And the key thing is when you break your fast
and you eat protein, it turns on your body's capacity
to stimulate the growth and the building up of new muscle.
Not if you have sugar for breakfast.
For me, being healthy means being able to get up
every morning and do exactly what I wanna to do, no matter my age.
In fact, I recently hiked 15 miles in the snow in the mountains of Patagonia.
I was sore and tired after, but so was my 28-year-old guide who was half my age.
And that's why I'm excited to share a supplement that's been a game changer in my fitness journey.
Timelines might appear.
As you age your mitochondria, the tiny energy factories inside the cells of your muscles and organs become less efficient. And this can cause your energy levels and muscle function to wane,
leaving you feeling too tired to do all the things you used to do and all the things you want to do.
But MitoPure can help you turn back the clock.
It's clinically proven to rejuvenate and invigorate tired, worn-out mitochondria
for improved energy, muscle strength, and endurance.
It's backed by more than 15 years of serious science.
And I can tell you personally that my workouts have never felt more productive
with noticeable gains in muscle and endurance
within just a few months of taking it.
And right now, Timeline is giving my community
an exclusive 10% off your first order of MitoPure.
Just head to timeline.com forward slash Dr. Hyman,
that's D-R-H-Y-M-A-N,
and start your journey to peak muscle health.
It seems that every day,
more and more patients come into my office
bringing ever-increasing amounts
of healthcare information with them. And I love it when this happens because it means people
are taking ownership of their health, but it also means I have to stay on the top of my game.
So as a healthcare practitioner, how do you make sure that when a patient walks into your office
and says, hey, I really want a Dutch Complete or a GI map, that you have the right answers and tools?
The answer is Rupert University. They are the number one educational institute for root cause
medicine with over 20,000 practitioners
a year learning about functional and specialty lab testing.
Not only do they have absolutely free live classes hosted every week, but they bring
in industry experts to teach in-depth six-week boot camps on all the most popular functional
tests.
If you want to level up your knowledge of functional lab testing, make sure to visit
RupertUniversity.com.
Before we jump into today's episode, I'd like to note that while I wish I could help everyone
by my personal practice,
there's simply not enough time for me to do this
at this scale.
And that's why I've been busy building
several passion projects to help you better understand,
well, you.
If you're looking for data about your biology,
check out Function Health for real-time lab insights.
If you're in need of deepening your knowledge
around your health journey, check out my membership community, Hyman Hive. And if you're looking for curated and
trusted supplements and health products for your routine, visit my website, Supplement Store,
for a summary of my favorite and tested products. Welcome back to another episode of the Doctor's
Pharmacy and Health Bites, where we take juicy little bites into current health topics. When it comes to fasting, there's a lot of misinformation floating around
and one of the most common myths is that fasting slows down your metabolism. But here's the truth,
it all depends on how you fast. It all depends on how you fast. Long-term fasting can have its
drawbacks like slowing down your metabolic rate as your body conserves energy or losing muscle. But when it comes to short-term fasting, the opposite is
often true. It can actually give your metabolism a boost. In today's episode, we're diving deep
into the science behind fasting and metabolism. We're going to break down the differences between
long-term and short-term fasting, and we're going to explore how your body responds to each,
and we're going to debunk some of the biggest myths out there. So whether you're curious about
intermittent fasting or time-restricted eating, or just want to better understand how fasting
impacts your hormones, your energy levels, and overall health, well, this episode is packed
with insights to help you make informed choices. So let's cut right to it. The first myth,
myth number one, fasting slows your metabolism. Well, many people
believe that fasting slows your metabolism, and this might be true in some extreme cases, but the
truth is it depends on the type of fasting you're doing. Long-term fasting could have negative
implications for your metabolism, but with short-term fasting, the opposite actually seems
to be true. It actually seems to speed up your metabolism. So let's break it down. What is long-term
fasting? Well, long-term fasts typically range from a full day to several days without food. Long-term fasts have
lots of benefits. It stimulates autophagy or cellular cleanup. It promotes the burning of fat,
clean fuel instead of carbs for energy. And it can be super beneficial for weight loss,
improving insulin sensitivity and lowering body inflammation. About 48 hours or more into a fast, your metabolism
starts to shift. The body may start to conserve energy, which results in a downregulation of
metabolism. Now, this is an adaptive response to prolonged calorie restriction. But because your
body doesn't know when your next meal is coming, your metabolism slows to conserve energy. Now,
why is long-term calorie restriction a problem? Well, over time, long-term calorie restriction without
adequate nutrition causes your body to go into what we call starvation mode. And this puts stress
on your body. In most cases, a little stress isn't a bad thing. It can actually be a good thing.
But prolonged stress is not necessarily good. Now, there's a concept known as hormesis.
This is kind of a good stress. It's
basically a stress that doesn't kill you but makes you stronger. And you get that with short-term
fasting, with exercise, a sauna, cold plunge, and that turns on all your longevity switches. Now
calorie restriction is a form of hormetic stress and it has its benefits. But there's also bad
stress which occurs when we undergo this stress for too long, and a slower metabolism could be the result.
So what caused your metabolism to slow down
during long-term fasts, during calorie restriction?
Well, hormones change.
Leptin and ghrelin change.
During prolonged fast, your body undergoes changes
in the appetite-suppressing hormone called leptin
and the appetite-stim stimulating hormone called ghrelin
or ghrelin or however you want to say it but basically that's the hormone. Leptin is a hormone
that's produced by fat cells and helps regulate metabolism and hunger. Kind of tells you when
you're full. When calorie intake is restricted leptin levels go down and that tells your body
that energy stores are low. Now this is a good thing for people who have a common condition called leptin resistance, which is when you basically have too
much food and your leptin levels go up and up and you become resistant to the effects of leptin.
And when you do fasting, it actually makes your leptin sensitivity better. So you're not resistant
to its effects, which makes you feel full. And then that stimulates the body's ability to regulate
your appetite more naturally. It also improves insulin sensitivity and leads to weight loss.
Now, in the long term, in non-obese individuals, when you fast too long, it can result in a slow
down of your metabolic rate. And that means you're going to try to conserve energy because
your body thinks you're starving. Well, ghrelin, which is the hunger hormone, will initially increase during fasting, making you feel hungry. Its job is to stimulate
appetite and food-seeking behavior, which is a good thing. When you're hungry, you're going to
go looking for food. Now, during longer fasts, more than a few days, then ghrelin levels start
to decrease. And studies examining three-day fasts have found that 24-hour mean grain levels actually
declined over the fasting period.
In other words, you know, a lot of people who are fasting report a decreased hunger
as you continue to fast.
So you might be hungry the first few days, and then after a while, you're not hungry.
Now, when you're less hungry, you eat less, and the body then adapts by slowing down your
metabolism.
Now, another thing happens when you fast too long. Your thyroid doesn't work out so good. A slower metabolism
is in large part related to your thyroid hormone level. See, thyroid is the master control center
of your metabolism. When you undergo long-term fasts or calorie restriction for longer periods
of time, it actually lowers your thyroid hormone production
and therefore your resting metabolic rate, meaning you burn less calories just sitting around.
T3 is the active thyroid hormone and it plays a really important role in regulating your metabolism.
During longer fasts, the body aims to conserve energy and the way it does that, it reduces the
production of the active thyroid hormone called T3.
So you don't burn as many calories.
That slows your metabolism.
Your body can conserve energy and become more efficient at using those fewer calories.
Now, this is good when we didn't have a lot of food around and we conserved energy.
And it was sort of built in to protect us from food scarcity.
But we don't have that anymore.
Now, as your metabolism starts to slow down, the body becomes resistant to weight loss. And then it makes it harder to continue losing weight without further
reducing calories. You get kind of a plateau. Now, of course, if you're not eating at all,
your body's going to continue to waste and you'll starve and die. But if you calorie restrict,
initially you'll lose weight, but then you hit a plateau. Now, it's a survival mechanism.
It's going to help your body conserve energy in times
of scarcity. Now, short-term fasting is good because it doesn't result in a slowed metabolism.
It does the opposite. It actually boosts your metabolism. So what's short-term fasting? Well,
there are many different types of short-term fasting. A few of the main ones include what
we call intermittent fasting. Now, that's an umbrella term for various fasting schedules
where you alternate between periods of eating and fasting.
There's a lot of different methods out there.
There's something called the 16-8 method,
which is 16 hours of fasting and eight hours of eating.
So let's say you eat between, let's say,
eight in the morning and four in the afternoon, right?
And then you're done.
And then you take the next 16 hours off
and you go to bed and you sleep and you wake up and you eat.
There's something called the 5-2 method,
which is eating normally for five days and dramatically reducing your calories for
two days. Or there's alternate day fasting, or you can do even shorter fasts like 12 to 14 hours.
Now, intermittent fasting focuses on more extended fasting periods, which may include skipping meals
or limiting calorie intake for whole days. But I think the better way to think about this is what I call time-restricted eating. And it's a specific form
of intermittent fasting that emphasizes eating all your daily meals within a consistent window
of time, like eight hours, 10 hours, and fasting for the rest of the day, like 14 to 16 hours.
Unlike other forms of intermittent fasting, time-restricted eating focuses more on aligning eating with the body's natural circadian rhythms and ensures all meals are
consumed within a set time frame each day. You can do 12-12 fasting, 12-hour feeding window,
where all your calories are consumed, followed by the 12-hour fasting period where food intake
is restricted. So basically you would be fasting after dinner from 8 p.m. to 8 a.m. the next
morning.
I mean, everybody could probably do a 14-hour fast.
Basically you eat dinner and finish at, let's say, 6 o'clock.
That means you can eat breakfast at 8 o'clock the next morning.
The calorie restriction is not a requirement.
It can be a side effect of condensing your daily food intake to a shorter time window because you just don't have enough time to eat that many calories.
And that's why time-restricted eating is so popular.
It helps you eat fewer calories,
which then leads to weight loss without having to change your diet.
But optimizing your diet quality leads to even more benefits.
We're going to discuss that later.
But there are some studies that show that regardless of what you eat,
it works, but it works better if you eat more healthy food.
Now, short-term fasting can actually reset
and even boost your metabolism when you do it correctly.
It does this by supporting fat burning and by supporting metabolic health.
And it modulates several fat burning hormones, especially insulin.
Now, high insulin levels block fat loss and it makes it harder to lose weight.
And intermittent fasting can change that.
Now, insulin is the fat storage hormone. And when you have a high insulin level, you can't lose weight. And intermittent fasting can change that. Insulin is the fat storage hormone. And when
you have a high insulin level, you can't lose weight and the fat gets locked in the fat cells.
So you can't even burn them. Research shows that intermittent fasting can help lower your fasting
insulin, which is especially meaningful for those with prediabetes or type 2 diabetes or those with
underlying metabolic dysfunction. And that, my friends, applies to 93.2% of Americans. That means somewhere in that spectrum of mild insulin
resistance to prediabetes to type 2 diabetes, 93.2% of Americans fall in that group, which is
terrible. And most of us would benefit from listening carefully to this podcast and actually
applying the principles here. And a big study, what we call a meta-analysis, which is a study
of other studies, found that intermittent fasting reduced insulin levels by an average of 13
milliunits per liter in patients with metabolic syndrome. And that is a lot. Okay, that's a lot.
A review of the literature found that intermittent fasting and alternate day fasting could reduce
fasting insulin levels in pre-diabetics by up to 31% after eight weeks.
That's a good thing because high insulin levels lead to heart attacks, strokes, cancer, dementia,
obviously diabetes eventually.
Now, some studies have even shown that patients were able to reverse their need for insulin
therapy just by therapeutic intermittent fasting when they're supervised by their doctor.
I've seen this over and over. When people eat healthfully, when they cut out sugar and carbs, when they narrow their eating window
to 12 minimum, but ideally 14 to 16 hours, it has dramatic effects. The other thing that happens
when you do intermittent fasting is you increase the level of something called norepinephrine,
kind of like adrenaline, right? This is your stress hormone. It's involved in the fight or flight response. And when you
intermittent fast, it increases adrenaline, which is a good stressor because it tells your body to
mobilize stored fat to burn for energy, which is a good thing. It also stimulates human growth
hormone, which is really important. It helps with fat loss and it helps you preserve muscle mass.
Now, this brings me to another common myth about fasting. As you've heard me talk about,
I co-founded a company called Function Health, which gives you access to over 110 biomarkers
for $4.99 membership a year. Now, when you want to see the impact of your fasting regimen on your
hormones and biomarkers, you should for sure check out Function Health before and after you do your
intermittent fasting regimens.
And we're going to put the link in the show notes. But if you go to functionhealth.com
forward slash mark, you can jump the wait list, which is about 300,000 people right now. So
little tip for me. Okay, let's get into the second myth. Myth number two, fasting causes muscle loss.
Your muscle is three times, maybe even more, metabolic active than fat and requires
a lot of energy to maintain it. Muscle contributes to about 20% of your total daily energy expenditure.
For every extra one pound of muscle on your body, you burn six to 10 extra calories per day. So
that's why strength training is so great. It actually makes you burn more while you're just sitting around doing nothing.
If you heard me talk recently, you probably know how much I love Himalayan tartary buckwheat,
a gluten-free seed loaded with longevity-promoting nutrients. My good friends at Big Bolt Health have been carefully growing and researching this ancient plant for years. After tons of
positive feedback from me and thousands of customers, they produced the world's first 100% organic Himalayan tartary buckwheat sprouted powder.
It's easy to digest, richer in vitamins and minerals, and contains up to 10 times more plant nutrients like rutin and quercetin.
I love this as a topper in my yogurt, a sprinkle on savory meals, or as an easy add to my smoothies and protein shakes.
The sprout powder has no fillers, additives, or sugars, and is farm sprouted and packaged in the USA. Right now, Big Bolt Health is offering
my listeners a special offer of 30% off this amazing product. You can try it now by heading
to bigbolthealth.com and use the code DRMARK30. Again, that's bigbolthealth.com.
When it comes to my health routine, AG1 is non-negotiable. It's like my insurance policy.
I know I'm getting my daily vitamins, minerals, prebiotics, and probiotics in just one scoop.
The biggest change I've noticed is in my gut health.
AG1's prebiotics and probiotics support digestion and help with bloating.
Research shows that 80% of people experience less bloating after just 30 days of drinking AG1.
I also trust AG1 because it's made with bioavailable ingredients,
meaning my body can actually use the nutrients. And it's non-GMO with no added sugar. So this holiday season,
try AG1 for yourself or even gift it to someone special. It's the perfect time to focus on
supporting your body with an easy and surprisingly delicious daily health drink. And that's why I've
been partnering with AG1 for so long. Every week of November, AG1 will be running a special Black
Friday offer with a free gift for your first subscription. In addition, the welcome kit with vitamin D3 and K2. So make sure to check out drinkag1.com
slash hymen to see what gift you can get this week. That's drinkag1.com slash hymen to start
your holiday season off on a healthier note while supplies last. Now during prolonged fasting or
calorie restriction, the body actually breaks down muscle, which is not good, especially if
you're not resistance training or if you're not eating enough protein.
Now, this loss of muscle is not a good thing because then you get a slower metabolism since
fewer calories are burned.
And that's why I don't regularly do prolonged fasts.
When I do this, I'm relatively thin, healthy, fit, don't have insulin resistance.
I have to be careful because I will lose significant amounts of weight and muscle if I do too long fast.
But I can do 12 to 14, sometimes 16 hours without a problem.
When you're fasting, you don't want to lose muscle.
You want to build muscle and maintain your muscle, not lose it.
Why?
Because muscle is the organ of longevity.
It's linked to a longer health span and your lifespan.
When you have a lot of muscle, it's linked to a longer health span, meaning you're healthy
longer and to a longer lifespan. And it does that through a lot of different mechanisms.
It lowers the risk of something called sarcopenia, which means less muscle. And that's really this
hidden disease of aging that affects so many people. Basically turning your muscle from a
filet mignon in your 30s to a Wagyu ribeye in your 60s or 70s, that's bad news. Even if you don't
gain weight, you can lose muscle, stay the same weight, and you become basically skinny fat. Also, when you
look at people who don't build muscle and strength training, they get osteoporosis,
and you can get chronic diseases like obesity, Alzheimer's, type 2 diabetes.
Now, when you have enough muscle, it helps protect against chronic disease by improving
your metabolic health. It improves insulin sensitivity and muscle acts like a sponge. It soaks up sugar and excess
fuel from your bloodstream. Now, having muscle also benefits your brain, which is kind of your
biggest muscle, not actually a muscle, but it's the thing that you use to run your life basically.
And if it's not working well, it's a problem. And so having healthy muscle
also leads to improved cognition, to mood, to mental health, and lots more. And that's why we
got to combine resistance training with any time-restricted eating or intermittent fasting
regimen to preserve muscle and get the maximum benefits. When you just do it without the strength
training, I don't think it's a good idea. Body composition is really important. And this is
really how much fat and how much muscle do you have, right?
Very simple thing, but it's often not looked at.
It's one of the most important diagnostic tests we can do.
Now, when intermittent fasting is combined with resistance training, meaning strength
training, your lean muscle mass is also preserved, which is a good thing.
Now, some studies suggest that resistance training while intermittent fasting improves
body composition by increasing
muscle mass and decreasing body fat. That's a good thing. And so this is really where we want to go.
We don't want to fast and lose muscle because that's a bad thing. Now there's a randomized
control trial of 41 overweight obese adults. They found that combining intermittent fasting with
calorie restriction and regular protein intake, about 25 to 50 grams per meal over eight weeks, led to greater reductions in
total body fat, in visceral fat, in other words, the inflammatory belly fat, and total body weight
compared to just calorie restriction alone. So the message here is if you're going to do
calorie restriction or time-restricted eating
or intermittent fasting, strength training is non-negotiable.
Intermittent fasting in this study combined with time protein intake and calorie restriction
positively shifted the gut microbiome to bacteria that help burn fat and improve your metabolic
health more than just calorie restriction alone.
Yep, your gut bacteria actually affect your weight. It's quite remarkable. But you got to make sure
you're getting enough protein. That's really key. And the ideal amount, if you're active,
is about a gram per pound of ideal body weight. So if you're 120 pounds, that's about 120 grams
a day. It can be 0.7 to 1, but somewhere in that range. And this really helps you fight muscle loss that happens during prolonged fast.
Now, here's a tip.
Break your fast with a meal that contains protein to halt the muscle protein breakdown
from your overnight fast.
And then you stimulate muscle protein synthesis.
So this is really important.
I want you to hear this.
When you fast, even if it's just overnight, right, from 12 hours,
from let's say eight at night till eight in the morning, you got to start your first meal with
protein. If you do what we do in America, which is eat sugar for breakfast, cereal, muffins, bagels,
croissants, sweetened sugars, sweetened teas, sweetened coffees, I mean everything that we typically eat in America,
it's going to kill you, I promise you, faster than if you eat protein. Protein will help you
live longer, be healthier. And the key thing is when you break your fast and you eat protein,
it turns on your body's capacity to stimulate the growth and the building up of new muscle,
not if you have sugar for breakfast. Fasting only
becomes a problem for muscle mass if you're not substituting calories and carbs with protein and
also adding resistance training. Okay, what's the third myth around fasting? Fasting increases the
risk of heart disease. Well, there's been a lot of buzz around articles attempting to debunk the
benefits of fasting. Some even link it to an increased risk of heart disease? Well, there's been a lot of buzz around articles attempting to debunk the benefits of fasting, some even linked it to an increased risk of heart disease, which doesn't
sound so great. Now, one study in particular caused confusion by suggesting that time-restricted
eating, specifically an eight-hour window, which is a 16-hour fast, right, was linked to a 91%
higher risk of cardiovascular death, according to the American Heart Association.
So that sounds terrible.
Now, for those with existing heart disease, the study claimed that eating in a window
of 8 to 10 hours per day was associated with a 66% higher risk of death from a heart attack
or stroke.
But let's kind of wait there for a minute and break this down.
Let's look at the limitations of the study, which were quite significant. First, the data came from about 20,000 US participants from what we
call the NHANES study, which is the National Government Study, the National Health and
Nutrition Examination Survey. Dietary information was based on two self-reported questionnaires and
relied on participants' memory, which is not really good. The data on dietary food frequency questionnaires shows that they're pretty unreliable. And there's a lot of bias, right?
People often misremember what they ate. They underestimate what they ate. They overestimate
the good stuff. They underestimate the bad stuff. Let's face it, we're all human and we don't like
to tell the truth. So it's really not an accurate way to evaluate someone's diet. And there's just
a lot of data on this. And I've written a lot about this, but it's something we need to really be aware of. These food frequency questionnaires can be helpful
for looking at maybe patterns or associations, but they don't prove anything. Second, the study
didn't account for what we call confounding factors that have influenced participants'
health or the decision to engage in time-restricted eating. In other words,
maybe the people who tried to do this were already really sick.
And so that's why they did it to improve their health, but they were already really sick and already had a high risk of heart attacks. And maybe it wasn't the time-restricted eating at all.
The other thing was that overall diet quality wasn't really paid attention to. So, I mean,
for example, some of the participants might do their fast, but then when they eat, they just
eat the standard American diet or have fast food or French fries or sugar or crap, right? So is it fasting that
caused the problem or is it the rest of their diet? And third, the researchers focused only
on meal timing and cause of death. They didn't provide other health data such as things about
your critical health factors that determine your risk, like how many calories are consumed during
the feeding window? What was the quality of the calories?
Was it whole foods
or was it the standard American ultra-processed diet,
which is what we mostly eat in America?
60% of our diet is ultra-processed food.
Of course, there's lifestyle factors
that they didn't account for.
Stress, smoking, alcohol.
Maybe the time of day they're eating is also important.
Fasting during the day and binging at night
is more problematic than eating during the day
and fasting at night. In other words, what if you didn't eat all day and then you had a giant meal
at dinner and then kept eating until you go to bed? That's going to have a very different effect
on your metabolism. So this is the premise of time-restricted eating or eating within your
circadian rhythm. While the headlines might sound scary, it's important to understand,
like any study, what the limitations are before you come to any conclusions. So is fasting dangerous
for some people? Yes. True. Who are those people? Well, if you're pregnant, not a good idea. If
you're breastfeeding, if you're trying to get pregnant, if you have thyroid issues, if you're
type 1 diabetic, or you're underweight or malnourished, all those things, or you're frail,
or you're elderly, or chronically ill, maybe not such a good idea. Now, fasting can trigger hormonal changes that cause your body to be stressed,
not something you want while you're pregnant or trying to get pregnant. Women who are trying to
get pregnant with PCOS, which is polycystic ovarian syndrome, or reproductive issues could
benefit from time-restricted eating, or at least eating within a 12-hour window. I think that's
just basic. The standard should be everybody should take a 12-hour break
from eating every day, right? Finish dinner at eight, don't eat till eight in the morning.
Finish at seven, eat breakfast at seven in the morning. That's not so hard. That's why I call it
breakfast, break fast, because we should be breaking the fast, not just eating until we go
to bed and then eating first thing in the morning. Now, intermittent fasting can also help reset
the body's internal clock. So what does that mean? Well this is your circadian rhythm. When you fast
it's really important to fast with your circadian rhythm not against it. So what do I mean by that?
Well human beings are biologically programmed to digest and absorb food best earlier in the day.
This is known as circadian eating. Dr. Sachin Panda is a lead scientist in
circadian rhythm research. That means doing daytime things when the sun comes up, like eating,
moving, and working, and nighttime things when the sun goes down, like winding down and sleeping.
Duh, right? Dr. Panda discovered that thousands of genes turn on and off at specific times of the
day, which affects lots
of different bodily functions. Your circadian rhythm affects your body's ability to digest your
food. Now, insulin sensitivity, which is really important, is highest in the morning and it
decreases during the day. Our digestive system produces less saliva, stomach acid, and digestive
enzymes at night, which is why late night eating is a bad idea. And yet it's what we do mostly in America. What happens when
you eat late? Well, it causes blood sugar swings throughout the night, makes weight loss harder,
it messes up your REM sleep, which is your dream sleep, and increases the risk of type 2 diabetes.
It also puts energy towards digestion, takes energy away from rest and repair. Because at
night your body's supposed to rest and repair and heal, but when it's digesting, it can't do that.
And time-restricted eating might also help extend your lifespan. A study on firefighters showed that
14-10 time-restricted eating, meaning 14-hour fast, 10-hour eating window, for six weeks improved
oxidative stress and reduced something called advanced glycation
end products, which is a marker of aging, inflammation, and cardiovascular disease.
Now eating an earlier dinner or fasting for at least three hours before bed can improve sleep,
it can support weight loss, it can improve your immune function and your metabolic flexibility,
and prevent chronic disease. So lots of benefits. So are the benefits
of fasting due to not eating, to calorie restriction, or eating within your circadian
rhythm? Well, it's probably a combo effect. So as we've explored today, fasting doesn't
have to be a metabolism-slowing monster. It's often made out to be. When approached correctly,
especially with short-term fasting methods like intermittent fasting, time-restricted eating, you can actually boost your metabolism. It can help you burn more
fat and it can improve your overall health. It's all about finding the right balance for your body
and your lifestyle. So whether you're looking to improve your metabolic health,
manage your weight, or simply give your body a reset, fasting can be a powerful tool when used
wisely. The key takeaway, don't fall for the myths and
understand the science behind fasting. Listen to your body. Your body is the smartest doctor in the
room. I always say that. Don't listen to doctors. Don't listen to the science. See how you feel and
how you respond and then learn from what your body is telling you. Also remember fasting is just
one piece of a puzzle.
Combining with a nutrient-dense diet, with regular exercise, with stress management,
it's going to give you the best results. Thanks again for joining me today on The Doctor's
Pharmacy and Health Bites. Don't forget to rate, review, and follow The Doctor's Pharmacy wherever
you get your podcasts. Stay healthy, stay informed, and I'll catch you next Friday for another episode
of Health Bites. Thanks for listening today. If you love this podcast, please share it with your friends and
family. Leave a comment on your own best practices on how you upgrade your health and subscribe
wherever you get your podcasts. And follow me on all social media channels at Dr. Mark Hyman.
And we'll see you next time on The Doctor's Pharmacy. For more information on today's episode,
please check out my new video and audio
podcast, Health Hacks. It airs every Tuesday and includes a more detailed breakdown of these Friday
Health Bites episodes. I'm always getting questions about my favorite books, podcasts, gadgets,
supplements, recipes, and lots more. And now you can have access to all of this information by
signing up for my free Mark's Picks newsletter at drhyman.com forward slash Mark's Picks. I promise
I'll only
email you once a week on Fridays and I'll never share your email address or send you anything
else besides my recommendations. These are the things that have helped me on my health journey
and I hope they'll help you too. Again, that's drhyman.com forward slash MarksPix. Thank you
again and we'll see you next time on The Doctor's Pharmacy. This podcast is separate from my
clinical practice at the Health and Wellness Center and my work at Cleveland Clinic and Function Health, where I'm the chief medical officer.
This podcast represents my opinions and my guests' opinions, and neither myself nor the podcast endorses the views or statements of my guests.
This podcast is for educational purposes only.
This podcast is not a substitute for professional care by a doctor or other qualified medical professional.
This podcast is provided on the understanding that it does not constitute medical or other professional advice or services.
If you're looking for your help in your journey, seek out a qualified medical practitioner. You can
come see us at the Ultra Wellness Center in Lenox, Massachusetts. Just go to ultrawellnesscenter.com.
If you're looking for a functional medicine practitioner near you, you can visit ifm.org
and search find a practitioner database. It's important that you
have someone in your corner who is trained, who's a licensed healthcare practitioner, and can help
you make changes, especially when it comes to your health. Keeping this podcast free is part of my
mission to bring practical ways of improving health to the general public. In keeping with
that theme, I'd like to express gratitude to the sponsors that made today's podcast possible.