5 FASTING SECRETS To Lose Weight & Prevent DISEASE! | Lewis Howes

The more dopamine, the more pleasure, the more we like the food. That's what good tasting food means, because it stimulates more dopamine production. And the consequence of hyper-stimulating our brain with dopamine means we overeat and we become obese. And that's why two-thirds of people are overweight is because they- this video is.

Sponsored by Inside Tracker and you'll hear more about them in just a minute. What are the insane benefits of water-only fasting? Because you've been doing this for 38 years. with over 20,000 patients that have done water-only fasting. What are the main benefits? Well, you know one of the first.

Things that we look at is that there are certain conditions that are really common today. So, cardiovascular disease, high blood pressure, diabetes type 2, autoimmune diseases where the immune system itself is attacking the body, rheumatoid arthritis, ulcerative colitis, Crohn's disease, ankylosing spondylitis, the psoriasis, the eczema, these conditions where It's your own body that's kind of working against you. And also certain types of cancer like lymphoma. And these conditions that are so common now are really thought to be unmanageable. Because I mean if you go to a physician with high blood pressure, they're going to give you a medication that might be a diuretic or a beta blocker or whatever, a combination of medications and they're going to tell you right from the beginning, if you do what I tell you, you'll never get well. Really? You'll be on these meds for the rest of your life. Absolutely, they're telling you, you'll never get off these meds, you'll be on drugs forever because they know that they're not actually dealing with the reasons that you've developed high blood pressure. The root. You're dealing with trying to manage the consequence of the root. And so our approach is a little different because we're not interested in trying to come up with a pill, potion or powder and tell you, well, that's it, just take these drugs and except for the consequences.

Keep eating the same way, keep living the same lifestyle, keep lacking sleep, being stressed, eat all the processed foods, and you'll be on these drugs for the.

Rest of your life.

Well, live normally. Yeah, right.

Normal the way it is today. Well, two-thirds of people are now overweight or obese. So, being overweight is normal. If you want it, doesn't mean it's healthy. You don't necessarily want to be normal if you want to be healthy, because normal are average. right now is in trouble. And it's in trouble because people are under the influence of the pleasure trap. There's this hidden force that's undermining people's health and happiness and they don't even realize it in many cases.

Delayed gratification is the key. That is the way, in my opinion, not living in the instant pleasures of today, but how can I distance myself from it as long as possible to be rewarded in other healthier, happier ways?

The problem, I think, is though that you are biologically designed for short-term pleasure seeking self-indulgent behavior. Those hits, those dopamine hits. Absolutely. The body, the brain rewards the body every time it engages in behavior that favors survival and reproduction. And those primary dominant behaviors are feeding behavior and sexual behavior. Because it's food and sex that are necessary for the species to survive, to get enough to eat, to not get eaten, live long enough to reproduce. And that dopamine-driven short-term response worked great through most of human history. but more recently it's become a bit of a trap. And it's become a bit of a trap because we've changed our environment from an environment of scarcity where it was really hard to get enough to eat people.

To abundance. To abundance.

And now we live in an environment of abundance and these highly processed foods are so appealing because they play off those ancient mechanisms.

The salt, the sugar, the processed nature of it, it's just delicious but it's not good for you.

Well, you have to override that biology if your goal is to survive long and well.

Yeah, not survive unwell, which is what we've trained our society to do. It's like, how can we extend our life on machines? That's not a well-lived life. But how can we be happy, healthy, fulfilled, and then have a quick, quicker death, right? It's like not suffer for as long as possible, but live as long, happy and healthy, and then turn off the lights.

Well, we talked about having a good life, hopefully long life, but also a good death, the death where one night you go to sleep and you don't wake up rather than spending the last 9.6 years unable to talk or move lying in some nursing home bed waiting for people to come and change your diaper because you've had a stroke or you've had other debilitating illnesses that prevent you from actually making the last decade or two perhaps the best, most enriching time of your life rather than the worst. dependent on others around you, unable to really function properly. And that's the price we pay for short-term pleasure seeking self-indulgent behavior that doesn't necessarily cause an immediate problem, but definitely causes longer-term problems.

So what are these crazy benefits of water-only fasting? What are the main things you've seen.

People transform of these 20,000-plus cases? One of the biggest thing that fasting does, it's an efficient way of undoing the consequences of dietary excess. So people spend a long time accumulating the consequence of dietary excess and they can very rapidly reverse many of those consequences. Such as what?

What are the main things you see? So the conditions like of that are.

Caused by dietary excess, so high blood pressure for example. We did a study with 174 consecutive patients with high blood pressure and 174 people were able to lower their pressure enough to eliminate the need for medications. The medications for blood pressure chronic cough, fatigue, impotence, and premature death. And yet they're routinely used because it's not recognized that blood pressure is a reversible and containable process. Really? Fasting is an effective and efficient way of reversing and normalizing blood pressure. Now the problem is you can't fast forever. You have to feed. So you also have to learn to eat a health promoting diet in order to sustain those results. But in terms of eliminating the risk factors, eliminating the need for medication, normalizing blood pressure, you can do that very predictably with medically supervised water only fasting.

What does it mean medically supervised? When you're just drinking water, I mean, why do you need someone there to watch you? Is it like testing with your blood sample? Is it just making sure you're not fatigued? In starvation mode?

We recognize that fasting can be done safely and should be done safely every day by every patient for 12 to 16 hours, depending on their goals. If they're trying to lose weight or gain weight, it may depend on the duration, but we recommend a period of 16 hours a day of fasting, eight hours a day of feeding. And by limiting the feeding window, as people like Walter Longo and others have pointed out, you may be able to induce some of the benefits that happen with long-term fasting cumulatively and also prevent perhaps some of the overeating and other things that contribute to dietary excess. So everybody can and should fast every day. In fact, everybody does fast every day. When you're sleeping, you're not eating. You break it with breakfast in the morning. It's an interesting process. So we're talking about maybe extending that natural period daily so that you aren't necessarily eating three or four hours before you go to sleep. It may improve your sleep quality, may improve digestion, may improve your muscle to fat ratios over time, and may induce changes that are beneficial. The thing that we do in addition is we'll extend that period much longer. The problem when you start talking about long-term fasting, and we're fasting people anywhere from two to 40 days on water only, is that first you need to make sure that the person is an appropriate candidate for that longer term intervention. People that have certain pathology, people on medications, people who have risk factors may be better off with a different approach than long-term water-only fasting. So first thing is a history and an examination to make sure there isn't any primary issues with kidney or cardiac function or medications that would contraindicate fasting.

What happens to the kidneys or the liver if you're water only fasting?

So the kidneys and liver are main detoxifying organs in the body and particularly the kidneys. If kidney function isn't at least at some minimal level, in our clinic we use creatinine levels of 2.0 as an arbitrary marker. If kidney function isn't adequate, then the rapid detoxification that occurs during fasting where the body mobilizes and eliminates both endogenous and exogenous toxins into the bloodstream and then are processed by the kidneys. If the kidneys function isn't adequate, you could overload the kidney function and create problems there. Really? And so it's very important that people have minimal levels of clearance. And that's also the reason we make sure that people have adequate fluid intake and maintain electrolyte balance and hydration. So we're monitoring people's electrolytes to make sure that we don't get into problems with potassium or sodium or other things which could become a problem, especially in.

These longer, faster ones we're going.

2, 3, 4, 5 weeks or longer.

Wow.

What's the longest someone's been on a.

Water fast with you? Well, in our clinic, we limit fasting generally to 40 days. We've had a few patients we've had to go a little bit longer than that. But there's evidence in the literature of patients fasting in medically controlled settings for.

As long as a year or more. So not that we would recommend that. Is that just someone who's so obese that they're trying to get rid of.

All the complications and shed the weight and all those things? There was a lot of work done in the 70s and 80s in treating supreme obesity with long-term fasting. But even a thin male, say a 70-kilogram male, could probably fast somewhere around up to 70 days if they're resting during the process. Not that they should necessarily do that.

Right, they could survive.

But as far as nutrient reserves and adequacy, the body is pretty amazing. You know, the main burner of glucose for humans is our brain.

Is what, just thinking or what?

Like cognitive activities, the brain we have this ridiculously large brain in humans, two and a half times that say of a chimp. It's huge and it's our main burner of glucose. In fact, if it wasn't for our ability to change our brain fuels from sugar to fat, we couldn't have survived as a species the way we have. Because if we had wandered away from the tropics after a week or so, if spring came late, we would have died. In fact, we did. The humans that didn't have the ability to change brain from burning sugar to burning fat, weren't able to survive. We know that because today virtually every human being has this ability to change its brain fuel from sugar, which is the normal fuel to burning ketones or beta-hydroxybutyric acid in particular. And that would suggest a biological adaptation, such an important adaptation that the species had to have it. So today humans can wander away from the tropics, spring can come late and we can survive despite our very large brain. and it's huge burning of glucose because we have this ability to fast. All we've done is taken this ancient biological process and applied it in a very unnatural situation, and that is a situation of dietary excess. No other animals maintain obesity. I mean, even whales, who you think of as kind of fat, are 9% body fat. Really? Yeah, they just hold it on the outside of their skin. They're lean mean machines, like all animals do, unless they get access to high hyperprocessed foods like humans eat. So if you feed human style hyperprocessed foods to animals, they also get fat. We add chemicals to our food specifically to induce dopamine stimulation in our brain. Those chemicals are salt, oil, and sugar. These are not foods, they're food byproducts. They're hyper-concentrated food byproducts. They're essentially chemicals we're putting in the food to stimulate more dopamine. Dopamine is the neurochemistry associated with pleasure. The more dopamine, the more pleasure, the more we like the food. That's what good tasting food means, because it stimulates more dopamine production. And the consequence of hyper-stimulating our brain with dopamine means we overeat and we become obese. And that's why two-thirds of people are overweight is because they fooled their brain with chemicals they put in their feed. It works in rats, it works in mice, it works in humans. Put the chemicals in their feed, they overeat, they get fat, then they develop obesity. and metabolic syndrome. And if you have metabolic syndrome, you're more vulnerable to dying from heart disease, cancer, diabetes, and even viral infectious diseases like COVID. The higher your metabolic syndrome increases risk.

Of dying from all these things, all these downstream consequences. What about olive oil or avocado oil?

I hear these good oils, these fatty oils are supposed to help you in certain ways.

Is that?

Well, you have to be careful when we define these good oils. There are oils that are more harmful than, say, olive oil. So an oil being less harmful doesn't necessarily mean it's good. It's just less bad. So oils are all highly processed, fractionated foods with nine calories per gram and limited satiety feedback. So if we're talking about trying to lose or maintain optimum weight, oils would have a disadvantage compared to eating your fat from a whole food. So I would advocate it. Avocado oil, eat avocado. Not necessarily process it down, remove the fiber out of the good components and be left with the oil. And the same thing is true with sugar. You need carbohydrates as a primary fuel, but you eat whole food, whether it's fruits or vegetables or starches, not necessarily the highly processed, hyper-processed byproducts of the food industry. If your goal is to avoid overeating dietary excess, obesity and the diseases of dietary excess.

People age at different speeds, and the date on your license may not represent your inner biological age at all. And if you're looking for ways to extend your health span and slow down the aging process, the keys to your health and longevity run in your blood. That's why Inside Tracker provides you with a personalized plan to boost your metabolism, reduce stress, improve sleep, and optimize your health for the long haul. It's created by leading scientists in aging, genetics, and biometrics. InsideTracker analyzes your blood, your DNA, and fitness tracking data to identify where you're optimized and where you're not. You'll get a daily action plan with personalized guidance on the right exercise, nutrition, and supplementation for your body. Add InnerAge 2.0 to any plan for a of calculation of your true biological age to see how you're aging from the inside out. And when I got my results back from InsideTracker, they told me and I quote, Louis, you're beating the clock. And that feels good. And now that InsideTracker has shown me my biological age, they are now providing an action plan of science-backed recommendations with the goal of improving the quality and quantity of the years ahead. For a limited time, get 20% off the entire Inside Tracker store. Just go to inside tracker.com/school-of-greatness for more. What's the three main benefits you see? It's hard to different. There's so many benefits.

It'd be hard to say which are the three. But I can talk about some of the benefits that we see. Certainly, you see weight loss. You can't help that. The laws of physics and thermodynamics say if you don't eat, you're going to lose weight. We know that weight loss is about a pound a day. Now that pound a day, a water only, average weight loss is a pound a day. Now some of that's water, some of it's protein, some of it's fiber, some of it's glycogen and some of it's fat. And of that fat, some of it's.

Adipose tissue, some of it's visceral fat.

The visceral is what you want to burn, right? Well visceral fat is the one that's most associated with pathology. In fact, probably shouldn't be very much visceral fat. Visceral fat's what happens when the body has no place else to put fuel, and so you'll store some additional visceral fat. And the higher the visceral fat, generally the worse you are, simplistically speaking. And so we just did a study where we took a DEXA scanner that has software that allows us to do precise whole body composition. So not just how much fat and protein there is, but how much visceral fat there is.

Internally and externally, right? Exactly.

So visceral fat, typically you think about an apple or a string in the belly, around the organs, that internal fat.

So, a lot of visceral fat around the organs as well, right? That is not good for you.

Yeah, that's not thought to be very healthy.

I mean, the belly fat that people see is not good obviously, but the stuff that's surrounding all the organs is you don't want to have a lot of that fat, right?

That's correct. And so, the question is what can you do to get rid of it? And any type of dieting will cause various types of body changes, but the approach that's shown the most effective at mobilizing visceral fat is actually fasting. Fasting is the highest ratio of visceral fat to adipose tissue mobilization. For example, a typical patient in the study might lose 20% of their fat but would lose over 50% of their visceral fat during a couple weeks of fasting, even though they only lose 4% of their lean tissue. And what's even more exciting is we look at, okay, what happens during fasting? Let's say, for example, a person loses 10 pounds. And we know some of that is water, some of it's fiber glycogen, some of it's adipose tissue, some of it's visceral fat. Then what happens after fasting? So you lose 10 pounds, you might regain five pounds. You're going to gain about two pounds of glycogen because you have sugar stores in your muscles that'll be depleted within a couple days of fasting. You're going to rehydrate because there's a little physiological dehydration during fasting. You're going to put fiber back into your gut because your gut's not going to have had fiber being added to it. You're going to pump up your muscle cells again because you will have depleted a little bit of glucose in order to maintain the glucose, the core glucose that your brain needed. And you're going to theoretically put back on fat. But after fasting, assuming a person adopts a whole plant food SOS free diet, what we found was weight comes off, weight comes back on. But the weight that comes back on is glycogen, water, fiber, and protein, not fat. Fat continues to drop. I like that. So we have We've been able to show, and this study will be coming out later this year, exactly what happens. And then we followed people at six weeks, brought them back in, re-analyzed them, and we're able to demonstrate that not only can people lose their fat and visceral fat, but they can continue to lose their fat and visceral fat, even free living, eating health promoting.

So the scale will go up some, but the fat will not go up. That's correct. So you gotta trick your mind and say, well, I'm not gaining all this weight, like you're gaining the necessary weight that your body needs to be stronger so you can have an active lifestyle.

And all these things.

But not the fat back.

Keep in mind, it's not weight per se that's the threat, it's excess fat. So for example, if you work out, you might gain 10 or 20 pounds of lean tissue over time. That's not necessarily compromising your health just because you gained weight. Now, if you sit around on the couch and eat greasy, fatty, slimy, dead, decaying flesh and highly processed foods and put on a lot of fat, particularly visceral fat, gain that same 20 pounds, that might be a problem. So we want to be careful not to be thinking just in terms of weight, but in terms of body composition. Okay, so the idea is to lower the fat, not necessarily lower the muscle.

Fasting is like eating, right? It can do a lot of good for you or a lot of damage. And so I would say that you're starting to see lots of clinical studies and preclinical, so animal studies, and at a certain point you put it together and you get a good sense for what works and what doesn't work. It doesn't mean it's not by no means final, but you get a good sense. So I would say if you look at the daily type of fast, what clearly works and is not associated with any negative effects is 12 hours. 12 hours of time restriction.

Yeah.

Don't eat for 12 hours.

Yeah, don't, yes, say 8:00 a.m., 8:00 p.m., stop eating at 8:00 p.m. and no more food until next day, 8:00 a.m.

Okay.

So that, I would say, I've never seen a negative study about this.

So if you wake up, you eat between eight and eight, you're good. Don't eat before 8:00 a.m., don't eat after 8:00 a.m.

So that's already a very good one. Another one, now if you go to 16 hours, say 16-8, you're starting to see lots of benefits, but you start seeing lots of problems.

What type of problems?

First of all, gallstone. formation, right? Gallbladder operation, gallstone formation, they double between the people that fast for 10 hours and people that fast for 18 hours, right?

Really?

Yeah.

So just to give you one, another one, study after study after study, and we've done the same study, but somebody has published it before we got a chance to, people that skip breakfast, most people that go 16 hours will skip breakfast, and the breakfast skippers tend to live less, have more cardiovascular disease, have more Disease in general.

Okay, wait a minute, let me break this down. So for years, I was always eating breakfast because I love breakfast. Then I heard about intermittent fasting, which is like skip the breakfast and eat at lunch and do the eight hour window, right? But you're telling me now that the studies are showing that those that skip breakfast are living less and having more problems than if you eat breakfast and eat within the 12 hour window.

No.

If you just eat breakfast.

Eating breakfast against not eating breakfast.

Gotcha.

So just eating breakfast, what are the studies showing now between not eating breakfast and eating breakfast?

Yeah, so the people that skip breakfast, they're living shorter with more diseases.

Really?

And then study after study after study.

It'S not one, you know, it's very consistent. Is this for people, you know, over.

60 years old or? No, no, no. Yeah, this is just looking at people, did they have breakfast or not? and then follow, you know, let's say for 20 years, the mortality of those that historically never eat breakfast.

Are there other conditions around that where they were over stressed or they were, you know, didn't have good relationships or.

They adjust for most of it, but it's possible. But my point to those that say, well, maybe it's something else, it's not the breakfast skipping. Yeah, I say, but if it's so beneficial to go 16 hours a day of fasting, why doesn't it at least bring you back to normal life?

Interesting. So, why is breakfast so important?

Well, nobody knows, but it could be that it's setting up the metabolism, right? It's setting up the metabolism to be, you know, like we were discussing earlier. So, if it's affecting the way you burn fat, if it's affecting the way your insulin functions, et cetera, et cetera, eventually, you could be more prone to insulin resistance, diabetes, cardiovascular disease, et cetera. You don't need very much. And also the heart, right? So it could be the ketone bodies, this continuous high level. So when you fast, these ketone bodies, this is what the word ketogenesis comes from. These byproducts of fat are going up in the bloodstream, right? And also fatty acids, right? The fat themselves. and these can alter the way your heart works and the way your brain works. So, we don't know, but it is possible that by having lots of that all the time, now some of the systems now develop problems and not improve.

So, it's okay if you're doing a week-long fast or a three-day fast to obviously skip the food or have less food during breakfast, but you're saying skipping breakfast on a consistent basis has proven that it's not a good thing.

Yeah, I mean, obviously nobody did an experiment where they said, well, let's randomize that 10,000 people and you skip breakfast and you don't and let's wait 30 years, right? They cannot be done. But it's epidemiological studies. So, you look at the databases and you say, the breakfast keepers, are they doing better or worse than the non-breakfast keepers? And they're doing consistently worse. And this is why you want to say, okay, if you want to do 16 hours, talk to a doctor, fine. It could help you, you know, do it for a month or two, but then find something else. Yeah, find something else. Because, you know, it does have a beneficial effect. It can have lots of good, could do lots of good things, but then eventually you don't want to keep it for 20 years. Yeah, so that's the sort of daily stuff. Once you get to alternate day fasting and all that, I think it's just crazy stuff, you know. It's just, you know, I always say I have a difficult time asking people to go from four coffees to three coffees a day, right? So when if you go to someone and say, oh, from now on beside the potential, you know, long-term problems that we just discussed, right? So if 16 hours does that, what could happen if you don't eat every other day, right? But beside that, just the feasibility, the fact that people are actually going to do this, it's just extremely unlikely. You're looking at one person out of 100, maybe they can not eat every other day.

Right, right. What about one day a month? Like, I'm gonna do a 24-hour fast one day a month.

Is that yeah, and nobody knows, right? Nobody knows. The problem with that, and this is.

Why.

My lab and my group has always focused on developing this fasting, making diet, is that in the one day you don't quite get into the ketogenic mode.

Right?

In one day of fasting.

Yeah, in one day of fasting. So you struggle because most people.

Will.

Not view that positively. I mean, you know, tomorrow or next week, I'm not gonna have a day where I don't eat, right? So it's a struggle. And also, you don't quite get, so you're hungry for that 24 hours and you don't quite get into a fat. a starvation response mode. That's why we're saying probably the system, if you look at our history.

Most.

Likely we can't go back in time. Most likely in the summers we had the job to get fat.

Fill up for winter.

Lots of fruit, honey, whatever you can get your hands on. eat as much as possible. And then the diabetes and pre-diabetes, you know, the insulin resistance that then leads to diabetes, so insulin doesn't work as well, it was probably part of that process of making you store fat. Put away as much fat as possible. So now, you know, this can be activated any time of the year, right? Because people overeat all year long. And so, probably not probably what we see now clinically is that when you do, let's say five days of a fasting mimicking diet or it could even be water only fasting, you unlock that. You seem to unlock that mode where, and this is why the doctor that I was telling you about, you see even, you see him even using the fat, the longevity diet, but it's still not quite losing that insulin resistance. until it does the fasting mimicking diet. That changes, and you clearly see the slope of the glucose levels curve. And so, probably- and the fasting mimicking.

Diet is around like 300 to 500 calories a day type of thing, is that right?

No, the fasting mimicking diet is the one for regular people is 1100 calories on day one, and then it goes down to 800 calories on day two, three, four, five, right?

Okay, got you.

So it's 800 calories. for the last four days. Gotcha. Okay.

Yeah.

So then the possibility is considering that over 70% of Americans are either overweight or obese. Now we're saying if you intervened a couple of times a year at least, and you remind the system we are not in summer mode. Okay, let's go into winter mode. Let's burn these fats because you know, we're no longer having to store him. Yeah, so that could be the trick of the five days versus, let's say, one day a month, which may keep the system confused and not sure did we reach another phase here? Is it, do we need to go now into a fat burning mode or can we stay in the fat accumulating mode?

So what's the difference between having the A fasting mimicking process of five days, 800 to 1,000 calories versus water only for five days.

I've done it, I can tell you the difference. I've done it one time.

With water only for five days.

And I remember every day of it. The pain of it, you mean?

Yeah.

To me, it was near-torture. And we knew that that was true when we did the, that I was telling you about the first clinical trial in 2009, I think it was here USC, on cancer patients and we thought, somebody has cancer, they're not gonna argue with water only fasting. They're gonna do it, right? We were sure, the oncologists were sure, let's go, let's do it. Nobody wanted to do it, right? So this is why we went to the government and said, we would like to develop a fasting mimicking diet, you know, for cancer patients. That's where it comes from, right? So it comes from from the refusal of cancer patients who are like, I'm.

Gonna eat no matter what. Well then, yeah.

It's just a safety issue. There's lots of things in food that are important to maintain high enough glucose level, high enough blood pressure, etc. etc. So once you remove it, I think people can do water only fasting, but.

Probably.

In a specialized clinic, you know?

Right, right, right.

Yeah.

So if you go to a place, it is effective. It is effective.

If you're in a specialized clinic in your house.

Yeah.

But watch out, right? Because again, as we were saying earlier, the devil is in detail. And if you go long enough, right? Especially if you're extreme and long, then the body goes into another response, which is thrifty mode.

So the body- Drifty mode, so it stops burning.

Yeah, then the body- It keeps the fat. Let's say you go a couple of weeks without food at all. The body now has to intervene and say, we're gonna be in trouble soon enough, right? So we're gonna keep that, we're not gonna burn this. We're not gonna burn. And so now you could have, and we know this from long-term calorific studies, you could have probably, nobody's ever figured out what it is, but it's called epigenetic change. so there's a switch that turns on and say, okay, from now on and maybe for years, I'm now in a saving mode. I'm gonna save energy. So now if you, and this is why the technology is so important, right? So you wanna do all the things that we just talked about and don't, you wanna avoid all the bad things, right? You don't wanna get into thrifty mode, you wanna get into the ketogenic mode, you wanna burn the, start burning the fat, keep that long term and avoid the side effects, you know. Yeah, so all of this, even though people think, oh yeah, it's an old thing, people used to do it, you see how the purpose, it was not to get to 110 years of age healthy back 2000 years ago. The purpose, if you were lucky, is make it to 50 years of age, and have children. So now everything changed, right? So now we can't just fast the old ways. We have to know, we have to be respectful of the tradition and what we learn from all these old practices, but at the same time we have to bring in the science, the clinical trials and say, okay, how do we, where do they match? You know, what's the common denominator between all these things?

Fasting is kind of a funky state because you're altering so many other things in the physiology, but one of the things that happens especially by about the second day of a water-only fast, is you really are seeing the impacts of what deep sleep can look like in a state that is totally absent food. And it's very interesting because you're competing with two forces, one that's keeping you awake and one that's helping you sleep a lot deeper. The one that's keeping you awake is cortisol. You have more of it, you have more stress hormones when you're fasting because that's the thing from a prehistoric standpoint that would've been going on, right? Fasting would trigger a signal that says, go get more food, right? Be alert, be focused, be alert, go get food. Like we don't wanna die. And so that's kind of keeping you awake. But the flip side of that is the total absence of nutrient is allowing you to get into this amazing sleep and your body temperature is really going down 'cause your body's turning down its metabolism. So I actually find fasting sleep to be some of the most amazing physiology because I'm watching this plummeting temperature rising heart rate variability, falling heart rate, all of these really valuable things, but a little bit of rising cortisol that can lead to shorter sleep times. But I still feel quite rejuvenated by sleep.

Wow. Okay. I want to stay on sleep for a second. I need to get the fourth one, which I want to close that loop.

But.

Does that hurt us if we nap throughout the day or take a power nap for 20 to 40 minutes? Does that help our bodies recover more even if we're doing the seven or eight hours of sleep or does that not matter?

You know, it depends. I would say naps are not a bad idea provided they don't reduce your drive to sleep later. So I just got back from like a hunting trip last month where just based, I mean, first of all, it was exhausting, right? You're sort of hiking 10 or 11 miles a day on vertical walls, you know, carrying a 50 pound pack. It's all the stuff that is physiologically as taxing as it gets at altitude, right? But there was no way you could go to bed any earlier than 11 and you had to be up by 4:30.

Really?

Well, just because you have the two times when you're going to have the best opportunity to go and stalk the animal is in the evening and in the morning. So those are the times. So, there was no way I was going to survive a week of that if I didn't carve out an hour and a half to two hours in the middle of the day to sleep. And I'm normally not a napper. But I made it a priority above anything else, including practicing with my bow and arrow in the middle of the day, which I would normally want to do. Nothing was a higher priority than getting that nap in during the day because I was deficient at night and getting that nap in the day didn't rob me of the ability to sleep at night.

You still were passing out right when you got on your pillow.

Absolutely. Now let's say we talk about a person who is getting seven and a half or eight hours of quality sleep at night. Is there any downside to a 20-minute power nap? I would say no. But if going any longer than that, I would be mindful of it because sleep comes down to balancing basically three things. The first is cortisol. The stress hormone cortisol must decline in the evening for you to be able to sleep. The second thing is you have to accumulate something called adenosine. Adenosine is like this metabolic breakdown product that corresponds to how much work we do physical work, cognitive work. So, more adenosine makes us more tired. That's how caffeine works, by the way. Caffeine blocks the adenosine receptor. So, it functionally makes you think you have less adenosine, and napping reduces adenosine. So, you just want to make sure you don't reduce it too much. The third is melatonin, by the way, which has to go up. So, good sleep is when melatonin and adenosine go up and cortisol comes down. So, I guess to close that out, I would say if you are sleeping so short during the middle of the day, and this is what I was thinking about on my trip, you want to try to replicate a full sleep cycle in your nap, which is about 90 minutes. So that's why I really said, look, I'm going to set aside two hours to take a nap in the middle of the day to get to give me one full sleep cycle because I'm clearly being deprived of one during the nighttime.

And is there Such a thing as too much sleep? If you're getting 10, 12, 14 hours of sleep every day consistently, does that affect the body in a negative way?

Really an interesting question, by the way, and quite a controversial question in the sleep literature. So there is no question that hyper sleep has been associated with poor outcomes. So, you know, there's a inverse U, or sorry, a U-shaped curve of mortality with sleep, right? So people who don't get much sleep have a higher mortality, and it's really more of a J curve, right? so they kind of, you know, as you get more and more sleep, the mortality comes down, down, down. But then it does sort of uptick. So you get these people who are sleeping a lot, and they're actually having worse outcomes than the people that are in the seven and a half to nine range. Historically, that has been explained by the fact that people who are sleeping a lot are usually sick, and that's why they're sleeping a lot. So we're not, we're missing, we got the arrow of causation wrong. We're saying, you know, are they sick because they're sleeping too much or they're sleeping too much because they're sick. While I think that the majority of the hypersleepers are hypersleepers because they are sick, there is actually some emerging evidence to suggest that absent that, there might be a downside in too much sleep. But again, I think for most people, most of us are on the other end of that spectrum, which is we're constantly battling the need to get enough. and that's either through, you know, our kids, our work, our stress, our electronics, our food, our alcohol, you know, all the above, our travel.

And is it a negative if you're a kid and you're eating a lot of junk food, you're not sleep, you're staying up late because you're whatever, playing video games all night, but you've got all this energy all day and you're active. Is there a negative for, in your early ages, teens, early 20s through lacking sleep, eating poorly, or is there a way to recover in your 20s from the damage you've done in your before 20?

Yeah, it's a good question. I mean, certainly you can break it down into sort of the behavioral habit side and you can talk about it through the physiologic lens. The good news is before the age of 20 or 30, we are pretty remarkably resilient. I mean, you're an athlete, so you can relate. How old are you now, Louis?

You're near 37.

37.

So you might not have fully appreciated, I'm 47, so I'm a full decade older than you. And when I think about 17 to 27 to 30 to 11 to 47, I can really talk about those decades through the lens of resilience. Like at 17, you could shoot me and I think I'd still get up the next day. Like you just couldn't, right?

You're Superman.

Yeah.

You're absolutely Superman. And I don't know, I feel like the first observation of not being Superman for me kind of kicked in about 42-ish, about five years ago, was the first time I was like, oh, so this is what people talk about, right? Like, you can't just go out and crush it every minute of every day. and I think that's just one lens, which is through the lens of exercise. But the same is true of physiology, right? Like, or I'll give you another example. Many of my patients have observed this. I've observed this. Like, I was never a big drinker in college, but certainly there were enough occasions in med school or college where I'd go out and drink far more than anyone should. And yet somehow the next day I could, like, get up at six in the morning and go and do whatever.

I need to do.

Like, I remember one night, actually, being out drinking until three in the morning. I mean, having so much to drink, it was ridiculous. And somehow getting up at six in that morning to do a hundred mile bike ride.

Oh my gosh, man.

Probably still partially drunk. But it felt fine by about two hours into the ride. Today, if I had three glasses of wine, the headache I'm gonna have the next day is gonna last me till the middle of the day.

Is that because your body was able to assimilate the glucose into the muscles and it used it to its advantage then? and now it's like, it takes over.

It's a very good question. I really, I mean, I could, I could sort of, you know, speculate on what it is, but I, I just think there's an over. So there's this thing called homeostasis, right? Which is one of the Hallmarks of Youth, and it's one of the Hallmarks of Aging. And, you know, it's, it's the ability to, or it's, it's our lack of homeostasis. We lose this ability to get the body back into the zone of optimal performance. So everything about the human body is very particular. For example, take pH, which is the amount of acidity in our we're so highly regulated like our body really needs to be at a pH of 7.4 so seven would kill you and 7.6 or 7.7 would kill you and this is a scale that goes from 0 to 14 to put that in perspective okay so tiny perturbations will kill you how good is our body at staying in that amazing temperature right you go much below about 94 you're dead you go much above about 104 you're dead How good are we at staying in that range? Oh, I mean good. I mean, we generally stay within a 1.5 degree band. So this homeostasis thing is amazing. It gets weaker and weaker as we get older. And so your ability to tolerate bad food, bad sleep, sedentary behavior, more stress, all those things, it just gets weaker and weaker and weaker. And I think it declines non-linearly. So again, what you experience is a decline between 30 and 40. It's bad. 40 to 50, yeah, that's worse. 50 to 60, you can fall off a cliff.

Is there a way to reverse this?

I don't think we know. I think you can definitely slow the progression of it. And, you know what? I would say you probably can reverse it, right? So just as you can clearly reverse diabetes, diabetes is a glucose homeostasis problem and it's clearly reversible. But, you know, so there are probably some variants of this that are harder to reverse than others. But no, I think we can reverse this process. But it gets harder, you know, it gets harder as time goes on. It gets harder the further you are into, you know, sort of the physiologic trap.

What are you doing to reverse it now that you've been experiencing this kind of not maybe a cliff, but a dip over the last five years for yourself? How are you thinking about it?

Well, I sort of had a change of heart five years ago. So actually six years ago, 2014. So I sort of hung up my bike, which at that point I'd switched from swimming to cycling is sort of my main sport. But at that point, a couple of things had happened. So, one, I had become very familiar with a lot of emerging research on excessive cardiovascular training, which again, is a rich man's problem.

Ultra marathons, ultra biking, ultra swimming, hiking.

That's right. That's right. So, again, and it's the same sort of curve, right? Where as exercise dose of exercise goes up, mortality comes down, but it has this little bit of a J where once you start to get into hyper amounts of exercise, especially over the age of 40, you're actually driving an increase in mortality. Now, really? Yes.

Does that mean running a marathon once a year or is it running a marathon every week?

Yeah, great, great point. Running a marathon once a year, probably not increasing your mortality at all. but running 40, 50 miles a week probably is, especially at that age. Now, again, this gets to your point about resilience. Someone in their 20s doing that doesn't seem to have any impact on mortality. It really only seems to be an issue if you continue. In fact, I did an interview with a cardiologist, James O'Keefe, on my podcast who is the world's expert on this and It was actually James's work six years ago because I heard him speak at a conference ten years ago. We became friends. I, you know, it's one of those things I'm sure you've experienced this where you hear something and you don't want it to be true. So you basically come up with all the reasons you're going to poke holes.

In it until you find the evidence the other way. Yeah.

Yeah.

Yeah. And eventually it became very difficult to ignore that this hyper amount of exercise was counterproductive. So that's one piece of the change six years ago.

It's probably bad that I just committed.

To doing the marathon next year yesterday. That's all right, though.

You'll be fine.

I just think don't do one a month.

Yeah, exactly.

And then I think the second thing was I realized, it was sort of funny, but I realized my prime was so far behind me that I needed to think about what was I doing this in service of, right? And not that I needed anyone other than myself to do these things, because I'm very self-motivated. So I don't, but just as a joke one day I asked my wife, I said, Hey, do you know what my PR is for 20K?

Like- Bike, run or swim?

Yeah, bike on a 20K bike on a time trial. And I was like, this is my wife. She hears me talk about this stuff all the time. I have spreadsheets and models and data, and I analyze my power data every single day. And I'm trying to break the record for San Diego. Like, I'm really so switched on to this. She'll probably get it within a minute. She'll guess what my PR is within a minute. she was off by 20 minutes, meaning she wasn't even in the zip code. So I was like, Huh, that's funny. Like, it's like literally the most important person in my life couldn't care less about this. And what I realized was, you know, I need to start thinking about a different sport, which is the sport of longevity. So what does it mean to be a kick-ass 100 year old? And so that was the the beginning of a mental model for me that in the past two years has gained much more traction called the Centenarian Olympics. So how do you train to kick ass at a hundred should you get there? And of course, everywhere along the way. So that now dominates my landscape of training, which means I don't, you know, care about how fast I can, you know, ride a 40 kilometer time trial. 'cause that doesn't quite fit into what a centenarian needs to be able to do.

What is your mindset going into a 40 mile bike then or some type of experience? Is it more the joy of it?

So, I don't, I don't, I don't, I don't train. No, my training is very specific, but now it is fundamentally organized around four pillars. So the pillars being stability, strength, mitochondrial or aerobic efficiency and anaerobic performance. And so each of those then has a super layer detail approach and I still ride my bike four hours a week. So it's a fraction of what I used to do, and it's now very much geared to a certain energy system and a type of training.

What was the fourth one?

Stability, strength, mitochondria, and- Mitochondrial efficiency or aerobic efficiency. And then the fourth and final one is anaerobic performance.

So you focus on those four metrics now on a day-to-day basis.

Yeah, yeah. Those four pillars sort of make up the training program, which is then in service of something that I invite every patient to define for themselves, which is because you will have a different set of variables for me potentially. But my Centenarian Olympics has 18 events in it. I want to be able to pull myself out of a pool where there's a one-foot gap between the water and the curb. I want to be able to hop over a three-foot fence. I want to be able to walk three miles in an hour. I want to be able to carry two 10-pound bags up four flights of stairs. I want to be able to goblet squat 30 pounds because that's about the weight of a kid. I want to be able to get up off the floor without using my hands. So I could rattle off all of my 18 things and you would say, Peter, those seem really easy and you'd be right as a 37-year-old stud. But the point is- As a 37-year-old.

A lot of them aren't easy.

Most 60-year-olds couldn't do this if their life depended on it and I have yet to meet but maybe one person in their 80s or 90s who can. And so that's the aspiration is to get to that level in your 80s or 90s. How do you work that backwards to inform your training in your 60s, in your 50s and in your 40s? And it's actually very hard.

And as I'm getting into, you know, I'm three years away from 40, what should someone in my age range be thinking about when they're, you know, I'm healthy, I feel good, you know, maybe have some aches and pains here and there when I'm training hard or something, but But for the most part, I feel amazing. What should I be thinking about moving forward so that I continue to feel amazing and have the ability to do these things?

I think it's never too late to at least become familiar with what these ideas mean. It doesn't mean that you have to go whole hog and devote yourself to this. I've obviously made a very conscious choice that I don't go to swim meets, I don't go to bike races. I don't train for those things anymore. and a big part of that is just time. You know, there are only 168 hours in a week, and, you know, I have a very clear set of priorities, and I'm willing to set aside 10 to 12 hours a week for exercise, which by many people's standards is still quite a lot, but probably by the standards that you exercise, and certainly by the standards that I used to exercise, I've never exercised so little in my life. So I have to be very efficient with every one of those minutes, and that means I'm laser focused on four principles of that. In your case, I think it comes down to saying, okay, how much time do you want to devote to the long game? How much time do you want to devote to the short game? Another way to think about this would be investing. If you're looking at an investment portfolio, you might say, How much do I want to put both time and money, so the actual capital I set aside, but also the amount of time I spend deliberating over it into my retirement account? versus how much do I want to invest as a day trader for short-term gains for money that I'm going to be using in the near term that's maybe even supplementing my income today? You could have totally different strategies for that, and that's totally fine. So I'm just in the category where I'm only thinking about long-term permanent capital. And so that's the first question is you have to decide how do you want to do that? And it might be that you say, Peter at 37, I just want to focus on running a marathon. I've always wanted to do an Ironman, so I'm going to go and do that. And, you know, I want to climb Mount Everest, and that's going to require, like, you might have a whole bunch of these bucket list things.

And truthfully, I would say do them.

Now because it's only going to get harder. Because you're not gonna be able to do it later.

Yeah.

Yeah.

I mean, I don't think you're going to want to do it later. So, so get those things out of the way. And how does, from all the research that you've done, obviously you've tested this for 10 years personally, but from the research and the science, how does fasting the right way play a role in anti-aging in your life and other people's lives?

The number one thing fasting or intermittent fasting regularly will do. And remember, it doesn't have to be a super long one. 14 hours can start, 16 hours is good. We're not talking heavy duty, you know, living in a cave kind of stuff. And that will stop you from having insulin resistance. When you have insulin resistance, it means that insulin levels go up and your body can't hear them, so they go up higher. When your insulin is higher, your all-cause mortality goes up. In other words, your chances of dying from every disease you can think of happens. What insulin resistance means is that when there's energy in your body, your cells are weak enough that they can't make good use of the energy. And fasting fixes that problem. When sugar goes up in the body, it forms something called advanced glycation end products. It basically cooks your tissues the way onions brown in a pan. And we know this from 30 years of anti-aging research about the effect of excess insulin and sugar the body. Fasting will fix that. But on top of it, there's something called autophagy, which is a core part of the recommendations I make, which is do whatever it takes to cause your body to turn its protein digestion mechanisms back on you. Because if it's not busy eating steak and eggs or, you know, tofu, if that's what you're into, it'll turn around and go, oh, there's some extra debris, some junk inside the cells, outside the cells. I can clean that up. and if you go a little bit longer, it says, you know what? I've got enough extra enzyme activity here. I think I will take out the weak mitochondria, these little power plant generators. I'll take out the weak ones and replace them with young, strong ones. And you start upgrading yourself internally because the stuff that would have gone into digesting the food you eat every two hours, because that's what someone told you to do in the 70s. Instead of doing that, you're eating the stuff in your body that makes you old. And when you control insulin, and you control autophagy, something very interesting anti-aging wise happens. And it's that you actually have younger and more abundant stem cells in your body. So intermittent fasting has proven to increase stem cells, increases testosterone, human growth hormone, and a huge swath of anti-aging substances in the body. And it's free. It costs less than eating breakfast.

And what's some of the new research about stem cells or the new developments that have excited you that everyone should know about?

Well, I've been pretty public about doing a lot of stem cells. I've had my bone marrow taken out twice.

And, you've been trying to convince me to do this for a while. I've been considering it. I still need to consider more.

It'll change your life. Anyone with old injuries like that, I have just no bodily pain and you get younger and there's really intriguing research about stem cells making brains work better, especially if you've had a traumatic brain injury, which I have had. And so you just get younger. And I can't tell you that it was stem cells alone that did this. I live a bulletproof life and all that, but I recently measured my brain's response time. This is an automatic response time. How quickly does the brain respond when a light or a sound comes on? So this isn't a conscious thing. And my response time is the average response time for a 20 year old. The response time goes down with, or goes up with age. So you get slower and slower as you age. I have a 20-year-old's ability to respond to the environment around me, which is pretty remarkable. And I truly think that the stem cells helped with that. There's also things like arterial flexibility, where I have the average flexible arteries of a 24-year-old when you just compare, and I'm twice as old as that, Louis. So something is working. I think stem cells are a core part of the anti-aging thing. What's happening now, though, is we're able to pull things that are like stem cells out of the blood instead of out of the marrow. And that's a lot less painful. And then I'm more open to that.

Than the whole sucking out of my bones. Yeah, it's spinning it up. You're asleep when you're actually, I was.

Awake one time when they did it.

Oh, man. So wait, what's this new blood drawing stem cell that you're talking about?

It's still getting regulatory approval, but it's called very small stem-like cells. But I'll show you the video sometime in that I'm laying on the table and the doctor has this thing and he hammers it with a hammer. Oh, no, I can't. And it goes, Every time I see that video, it's like it's the worst thing ever.

Man, yeah, you go through a lot of pain to have, you know, it.

Was really weird, Louis. It's almost like hunger. Like you can look at something as pain or just weird. And when I really dug into it, like there's the strangest feeling in my skeleton, but it wasn't pain. It was just so outside the universe of anything you would ever or should ever feel. that it, your body could say it's pain or it could just be like, that's different.

That's weird.

Yeah.

So I, I can say I've, I've been through much more painful things than that. But the idea that, that we could have younger and more stem cells by skipping breakfast is a little bit less money and time than that.

And that's why I think it's such an important practice. And what's this, what's this blood stem cell process, then? It's not, it's not available yet, but have you tested it?

What are there's a very few doctors who are offering it today. And I think it's in a bit of a gray zone from a regulatory perspective.

Have you tried it?

Very small stem-like cells.

Of course I've tried it. How do you feel about it?

Well, I think it's hard to say to compare A versus B. There's a lot more studies on getting stem cells from your fat or your marrow. There's also people getting stem cells from placental cords and umbilical cords or placentas and umbilical cords.

Right.

I have mixed feelings about that because if you're getting stem cells from eight different people, I'm like, how tested was that? And that makes all of my friends who do stem cells that way irritated that I would question it. Maybe it's perfectly good. I know a lot of people do it and love it. In my mind, I'm like, what do we test for every little virus and every little bacteria? And I kind of like the idea of growing my own stem cells, but that's not legal in the US anymore. It was for a while, and that was the most effective. That's crazy. It's coming down. We're at year one of an evolution that's happening, kind of like cell phones. The first cell phone, some guy in LA in his Mercedes 300D convertible, the whole trunk is his cell phone.

Yeah, exactly.

And it was $25 a minute. But with stem cells, it's come down in price a lot. The efficacy is way higher. It's getting better. It works better and better every year, but it still takes a doctor a lot of time to get the needles in all the right places and understand your joints. But man, it's a couple hours of relatively minor discomfort, but then you're better for decades. It's a really big deal, Louis. And I'll tell you, if you fast before you do that procedure, you have less insulin resistance, you have a working metabolism, everything you can do in a hospital, whether it's a surgery, whether you're getting a car accident, whatever, everything goes better if you just have a strong metabolism. And so, like, what do we all need right now? We want more resilience. Resilience comes from biology. The people who are best at taking fat or sugar plus air, combining them and getting abundant energy, those are the people who live the longest, have the best life, they have more opportunity for greatness because they simply have more electrons bouncing around in their heads to do stuff with. And it could power your immune system, it could power whatever you're doing in the world. But that's the core of everything I've ever done with Bulletproof, with all the content. How do you make yourself better at making energy? And it turns out sometimes not eating is part of the equation.

Yeah. And I'm curious, you know, everyone swears by the lifestyle slash diet that they live by that works for People who are vegan swear by it and the ones who are super healthy have lots of energy. The ones who are vegetarian, I feel.

Like vegans just swear. They don't even swear by their diet.

Is that just me? Who knows?

Yeah, I mean they swear by lots of things.

Sorry, vegans, I'm just teasing you guys. The vegetarian diet, people who live a vegetarian lifestyle for a long time say that this is the best for them. People are carnivore diet, say it's the best for them. Keto. Is there a worst type of diet, even though some of these things might work extremely well for particular body types?

What is the worst type of diet? The worst type of diet is the standard American diet. And, there's three things in it that are just horribly destructive.

Sugar.

The first one is... What?

Sugar?

Sugar is there, but I don't think it's as destructive as the other two.

Okay.

So, I'll give an order from the worst to the best of the worst.

Right?

So the number one thing that is wrong with the American diet is seed oils. These are omega-6 oils and canola, corn, soybean, safflower, sunflower, all this stuff that's in everything at the restaurant and most packaged foods at the grocery store unless you buy from the right company. It's full of these oils. These are the oils that drive insulin resistance. Your body takes these oils and they're all plant-based oils. and it says, I'm going to try to construct the outer layer of my mitochondria in my cells, these little batteries, but I have the wrong ingredients. So I'm going to make subpar batteries. Like if you go to the knockoff store and you buy the cheap batteries, they last a third as long as the good ones. That's what happens when you eat a lot of seed oils. Americans have about 40 times more of that oil in their systems than they should, and it gets built into your tissues. and that makes you weak. It is just not good.

Seed oils. Get over it.

Seed oils are bad. Second thing is industrially raised meat. It's full of xenoestrogens. These are estrogens that make animals fat on one-third less calories than normal. It's also full of antibiotics and it's destroying the soil of the planet right now. It also is depleting farmland when we take and we grow corn and soy. and grain, and we don't actually put the animal poop back into the soil the way we do on my farm. What we're doing is we're sucking all the nutrients out of the soil and we're creating a very, very big catastrophe 60 years from now. We'll be out of topsoil because we stopped having animals walk around and poop on it the way it works when you're doing a regenerative agriculture kind of thing. But worst of all, you eat industrial animals, they're also full of cortisol, and so you do this, they mess up your gut bacteria and they're full of glyphosate because it was on the feed and glyphosate disrupts your gut bacteria, your nervous system activity, and is tied to cancer. So we're getting bad oils. Oh, and those animals, because they ate corn and soy, they're full of bad oils too. So now you're like, man, the steak tasted good. And I had that nice salad dressing that came out of a bottle that was full of crap oils and you think you're being healthy, but you're completely wrecking things. And this some of the stuff that I did when I was heavy. And then the third thing would be sugar. If you have a ton of sugar, it's directly harmful. If you do the stuff I'm talking about, you can probably have a few grams of sugar and you won't notice that your body can handle it just fine. So sugar is not good for you and it is addictive, but it is way better to eat sugar than it is to eat corn oil.

But don't eat either one. Don't eat either one. Yeah, have sugar every once in a while. But don't eat oil and... Yeah.

If someone said, Here's a birthday cake, it's gluten-free, I don't do gluten. And they said, I made it with canola oil. I'd just be like, no. But if they said, I made it with sugar and butter, I'd be like, All right, I'm gonna have some. It's that big. The sugar, okay, your body can process that and it's gone. The other stuff, it sticks and it gets in there and you don't wanna do it. So the worst diet of all is that one with lots of fried stuff and bad oils. But the second worst diet for people who think they're being healthy this isn't going to be popular, but it is the vegan diet.

Why is that?

There's two things. Okay, I was a devout raw vegan. Okay, I did this for more than a year. I mean, I have bowls as big as my head full of kale and blended and mashed and sprouted and I mean, I'm good with rice and beans and everything.

Yeah.

Yeah, all that stuff. So what happens there is your body doesn't get the essential fats that it needs. We are not made out of plant oils. and I have in my books, I talk about the studies that show when you change the type of oil you eat, it changes what your body is made of. So when you go on a plant-based diet, you're getting two things. You're getting plant-based oils, which are not very compatible with you. Vegans will get mad at me and say, Dave, we can convert plant omega-3s to the good ones. Yes, it takes 45 grams of bad omega-3s to make one gram of the good ones if your body can do that, which it won't be able to do because you're on a plant-based diet. and then you get tons of these anti-nutrients from plants that cause cravings. When I was a raw vegan, I was always hungry. And I think that that's a very common occurrence. And I would say, well, that's great. I'm going to put more coconut oil or eat more, you know, fresh avocados, all these things. Avocados, it didn't matter. It's because plants don't want you to eat them and they cover themselves in defense systems that cause cravings. so I talk about the five big categories of things that are causing problems with us right now. And many plants that are common on a plant-based diet are not very compatible with humans. Like, oh, they have these vitamins. Yeah, they also stick to the stuff that lines the cartilage in your joints and gives you joint pain, or they inhibit your ability to absorb zinc and magnesium and iron and things like that. And so what happens is you tell yourself you're doing this to be nice to the animals. but what you're doing is you're making sure that the animals will go extinct because everyone was vegan, we'd have no animals. And then two generations later, we'd all be extinct because we'd have no animals to make soil. Because you can't grow carrots without animal poop at the end of the day. You can do it for 20 years, you can do it for 30 years, but eventually you have to build that soil back up. So what's happening on a plant-based diet is the wrong fats and lots of anti-nutrients. And that combination is kryptonite for people. And I've had tens of thousands of former vegans go bulletproof. And part of the reason I made the bulletproof diet was because I did harm to myself, including additional food allergies and worse hypothyroidism as a result of being vegan. And in terms of animal cruelty, I calculated deaths per calorie from eating a pound of grass-fed steak every day, which is a lot. You don't need to do that unless you're on the carnivore side of things, which there's an argument for that. But if you do that and the cow is grass-fed and local, unless the cow stepped on a frog, you kill less than one animal per year in all of your food. But if you eat boxes of processed soy nuggets, you disrupted the lives of whatever was going to live on that land and whatever the tractors killed. And so the number of deaths per calories is way higher for any grain product and anything other than basically fresh picked vegetables because of habitat destruction and tractor and like I asked a monk this in Tibet. I'm not dogmatic but I want to do what works. So I like to minimize suffering, buy from a local farmer, eat less meat but make it grass-fed and eat very good fats. And if you do that, you'll never have a craving during a fast. And if you don't believe anything I say, you can still be plant-based or vegan and you can still be standard American diet, Dave, I like my industrial animals, you know, go screw yourself. Just do intermittent fasting and you'll still improve. It works for any diet out there. and I'm happy to share the knowledge and I've moved a lot of information, there's 3,000 blog posts and stuff like that. But what I want people to do is figure out the foods that are compatible with your biology. And if you're one of the small percentage of people who's like, you know what? Vegetarian works for me. I know people, it really does. They eat some eggs, they eat some cheese, they eat a substantial amount of butter, and magically that really works for them and that's okay.

Right?

But if it doesn't work for you, don't tell yourself it's supposed to work.

So you'll do it even more. That's the mistake that I made. You're either in the fed state or you're in the fasted state. Okay? So when you're in the fed state, you're eating. Insulin is going up. And as insulin goes up, its job, like its normal job, is to tell your body to store those calories. Okay? So you can store it as glycogen, which is sugar, or it can store it as body fat. But that's the point. So you usually lunch or dinner. there's way more calories in that meal than you can use right at that point. So you want to store that. So when you don't eat, which is anytime you don't eat, it's called fasting. So when you fast, that means your insulin is going to drop, and that's the signal for your body to now start pulling those calories out of storage. And that's the reason you don't die in your sleep every single night, is because we have the ability to hold some of those calories in storage. So in the fed state, insulin goes up, you're storing calories or body fat. In the fasted state, you're not eating your insulin's dropping and you're using calories. So you're in one or the other. You can't do both at the same time. So if now you say, okay, when.

I'm eating, I'm storing. I'm not using calories. Is that right?

Every time I eat down, I will store.

I'm not burning body fat.

You're not burning body fat because you're putting in sugar, for example. and that sugar is going to signal that, hey, sugar's coming in, use the sugar that's coming in.

Don't burn anything off my body.

Exactly.

Keep all that stored fat, keep it. Just keep piling it on, right?

Exactly. So the only way that you can actually use the body fat is to let the insulin fall and not eat. So if you are now eating constantly, so the minute you get up, somebody tells you, oh, you have to eat, you can't skip breakfast, blah, blah, blah, and then you have to snack all day long. So now if you look at studies, the average duration of how long people eat for is about 14 hours and 45 minutes. That's the average. So if you start eating at 8:00 a.m., you don't stop till 10:45 p.m. That's on average. That's the average.

14 hours, you mean a 14 hour span of eating from the start to finish, right? You may not be eating every moment, but you're eating every few hours within a 14-hour window.

It takes about four hours for you to switch over into the fasted state. So the point is that before where you'd eat breakfast, lunch, dinner, and by 6:00 you're done, boom, now you shift into using those calories and your mom would say, oh, you need time to digest, right? That's what she sort of said. But the point was that you need to start using those calories that you stored up during your meal times. And that was the secret that they could stay relatively slim. Now, if you're eating constantly, then you never give your body a chance to switch over into that fasted state and start using those calories. The problem, of course, is that insulin stays high, which tends to keep your body storing calories. So, the high insulin, for example, blocks fat burning. You can't burn your fat stores because your body is like, the instructions that I'm getting is to store energy, not use energy. I want to keep my stored energy for when there's a time that there's no food. The problem, of course, is that there's never a time there's no food, right? Every day is the same thing, right? 14 hours of eating and no time of not eating. And that's the point. So now if you understand the problem, you can say, well, how am I going to change this? Well, it's simple. Increase the amount of time that you're not eating. And that's all intermittent fasting is. If you eat one meal a day, for example, or if you within an eight-hour window or a four-hour window or whatever, what you're doing is you're simply allowing your body to use the calories that have been stored, which is body fat predominantly. But that is precisely the reason you carry body fat. Like that body fat is not there for looks, is there for you to use, right? And that's the whole point. What's so bad about using it? If you don't eat, you're gonna burn it. Well, so again, go back to the 70s and everybody says, oh, you can't fast, you can't fast. Well, you know, they're eating breakfast, lunch, dinner. And if you're a naughty boy, you got sent to bed without dinner. So in town, you went from 12 o'clock to 8 a.m. 20 hours.

You look good the next day. You're looking clean. You got a six pack. It's burning fat.

Exactly. And nobody died. Nothing bad happens, right? There was nothing wrong with that. And hopefully you learned your lesson too, right? And that's the whole point, is that there's nothing wrong. It's a natural part of our human physiology. If we couldn't survive without eating. Like we would not be here today because when we were cavemen and cave women, they didn't have food every day. Exactly. They couldn't. There might be a stretch of three, four, five days where there was no food and therefore they had to survive on their own body fat, which they did. And that was the whole point. So let's let our body, you know, use it because that's the most natural thing to do.

What'S the process for you, your day-to-day life? Do you eat one meal a day, two meals a day? Do you fast every month for a day? Are you always doing intermittent fasting? Is there a downside to intermittent fasting? What's your process?

Yeah, I usually do a lot of sort of. I rarely eat breakfast, and I'll tell you that it didn't come. I mean, I started this in medical school, and that was mostly because I really wanted to just roll out of bed. go like, you know, I'd wake up literally like five minutes before I left the door. You know, I brush my teeth, put on some clothes and rolled out the door. I was, you know, it's just a, it's just that the way I was, right? And so I don't eat breakfast now because again, people say you have to eat breakfast, you have to eat, but there's actually nothing magical about breakfast. If you don't eat breakfast, what's going to happen? Well, my body, which is now burning fat because I've had eight hours of sleep, it's gone into sort of fat burning mode. because that's the storage form of calories or it's burning sugar, it's just gonna keep doing it, right? There's nothing wrong with it. So a lot of times I try and confine myself to sort of an eating window of sort of six to eight hours. And then once in a while when I get very busy, I will do a 24-hour fast, which is a one meal a day. And then every so often I'll do a longer fast. And the longer fasts are actually not as bad as you might think, but they really disrupt your schedule sort of socially. It's a tough one because a lot of our socialization happens at meals. So I often have dinner with my family, for example, and doing those longer fasts is really, really disruptive to that sort of thing, which is why when you look at traditional societies, like if you look at, say, you know, during major religions, for example, there would be a period of fasting that's sort of universal.

So, you know, everyone's doing it. So no one's feeling- Exactly. exactly. Because stressed when they smell the food.

Exactly. So if you're, if it's like good Friday or during Lent or during Ramadan for Muslims or, you know, during Yom Kippur for Jews or whatever, everybody's fasting. So it's actually terrifically easy because you're not disrupting the sort of social fabric of your life there. Whereas nowadays, if you fast, and I've done this, it's just really hard to do. It's not physically. It's not hard, but it's hard. And I do it mostly. you know, when I, when I've gained a bit of weight, usually after the holidays and after a vacation, I will sort of schedule a longer fast right after because I know that I can lose that weight very quickly. But that means I can enjoy myself. Like, if a couple years ago I went on a cruise and really ate too much, just a lot. I had a lot, and I knew it, and I could feel it in my pants were tight and stuff. So I did sort three or four day fast. And I'll tell you, by the next week, I was back to my normal weight. Well, that's great because a week and, but I got to enjoy the whole week prior where I really didn't look at what I was eating or how often I was eating or anything. I was like, this is my vacation. I'm doing this. But at the same time, I know, hey, I've got this next, you know, after this week, the week after, you know, very little to eat. And, and, and, and it gives you a great tool. to use if you need it, right?

Yeah.

It's almost like either every day don't indulge and balance and create a schedule where you're only eating in a certain window of time, whether before 4, 6, 8 hours, which I'm hearing is kind of the, which would be a great standard to have between 4 and 8 hours of a feeding time, is that right?

Yeah.

Yeah.

I mean, if you want to lose weight, you can do very well, of course, with a sort of standard 70s style sort of 8 a.m. to 6 p.m. which in a 14 hour fast every single night. Remember, they're doing 12 to 14 hours say every single night without even thinking about it. Like, that's a secret because they don't even think about that. That's just a period of time that they're not eating.

Right.

But now, of course, the, the, the, the traditions are different. You can eat anywhere you want. You can eat in the theater, you can eat at your desk, you can eat in the car. Like, in the 70s, stuff like that didn't exist. You didn't in a meeting in a boardroom, for example. Now you go to a meeting in.

A boardroom when there's food everywhere.

Donuts, donuts and cookies, right? Somebody's ordered a plate of bagels or something like that, right? It's like, well, why? We're having a meeting here, right? So that's the thing. So you could do very well with that kind of, you know, eight hour eating window, 10 hour eating window. You can do very well with it. But if you're not doing well, then you can extend it. And that's the beauty of it. You could extend it as much as you want. right? So if you think about fasting, you could go three days, you could go five days, you could go 30 days. People do that all the time.

But no food.

No food, yeah. So if you think about fasting, so the amount of energy that you need, so a pound of fat has 3,500 calories roughly. If you need about 1,800 calories, so that's for like a regular person, not like an athlete or somebody who's working out a lot. It takes about half a pound of fat per day. So, if you're dealing with a lot of obese people, like 100 pounds overweight, you could go 200 days, you know, if you want to lose 100 pounds, you could go 200 days without eating before you get- and survive. And survive, exactly.

And be okay.

Exactly. Be perfectly fine because this is a very efficient fat is an efficient store of calories, right? It's very efficient. That's why we developed this.

It's to keep you alive when there's no food around.

Exactly. So, you use it.

Does it affect your digestive system? Does it mess with your metabolism if you don't eat after a certain amount of time? And what happens when you start eating again? Does that affect your again, your stomach, your intestines, your colon, your metabolism? What's affected there? And this is the interesting part is.

That everybody thinks that fasting is like the worst thing you could do. When you actually look at the science of what happens during fasting, it's actually one of the best things you can do for yourself from both a mental standpoint and a physiological standpoint, assuming of course you're not malnourished, right? I mean, I'm assuming if you're the average American who's, you know, 10, 20, 30 pounds overweight, then this is something that actually has a lot of benefits. So there's a lot of sort of myths around it. One is that you're gonna burn a lot of muscle. And the truth is that you don't. I mean, when you, you know, if your body, your body stores energy as body fat. So people say, oh, you're gonna burn muscle. It's like, well, you've got to think that our body is so stupid that it stores energy as fat, but the minute you need it, it starts burning muscle. Why would our body be so stupid? And if it were so stupid, how did we survive? And it's like if you say firewood all winter for the winter, and then as soon as it gets cold, you chop up your sofa and throw it into the fire. It's like, why would you be so stupid? Our body's just the same. It's not that. you know, and I know and everybody knows that the way that you build muscle is that you exercise, right? So if you have, you know, lift heavy weights, then your muscles become stronger. It doesn't become stronger because you eat, right? That thing does nothing for building muscle. Like, otherwise we'd be, you know, the strongest nation on earth, right? But we're not. We're the fattest nation on earth. So that's the whole problem, right? I you're confusing two completely different things. There is a point during fasting where there is a little bit of protein breakdown and that's where people get very confused and say, well, you're burning muscle, but you're not. Protein is not the same as muscle. So our body has all kinds of protein, including all the connective tissue, like the skin and stuff that holds stuff in place. And some of that is often burned off. So, for example, when you look at those shows where people get surgery and they lose 150 pounds, they get all this flappy skin. That's not excess fat, that's excess protein. So that's, you know, it's functional tissue that you've never used up. So we actually see very little of that problem when people fast because there's a small period of time where they're actually using up the protein. The body will maintain its musculature based on what exercise and stuff you're using. So another big myth, so muscle burning is one thing. The other big, big myth is people talk about as starvation mode or metabolic rate. So metabolic rate is the amount of energy that your body uses in a day. the number of calories you burn in a day. And this is what we see if you simply cut calories. So this is a standard medical advice. Cut 500 calories a day and you'll lose a pound of fat a week. What happens, of course, is that you cut 500 calories a day and then your body quickly reduces the amount of calories it uses by about 500 calories. So now you're actually not losing any weight. That's what happens all the time because--.

Why does this stop why does it stop burning those calories?

Well, it stops burning calories by reducing its metabolic rate. So the metabolic rate is the energy that your body uses to, say, generate body heat, your liver, your kidney, your heart, and so on. We've known this for a hundred years that if you simply restrict the number of calories but keep the foods very similar, what happens is that your body is going to start using less. So because it doesn't like running a deficit, right? It's just if you normally make $100,000 a year and you spend $100,000 a year, now you make 50,000, you don't keep spending a hundred, right? It's, it's, you're gonna, you're gonna get thrown into jail. But so you reduce your expenditure same as a body. So it's getting less. So it's going to use less. And that's the natural reaction is, it's, it's important because it's a survival response. It cannot do anything different.

So it's almost like, so it's almost like you need to, be extreme in your use in order for it to burn and kill off these cells that might be harmful to you. But if you just do a little bit, I'm gonna eat a little bit less today, it's not gonna do that much.

It doesn't work. And people assume that if you go to zero, which is fasting, say you fast for a full day, you have zero calories, you don't die, right? Because what happens is completely different. Now you've lowered your insulin, so you're changing the hormonal profile of the body. and as you do that, you're now switching fuel sources. So instead of using food as your fuel, you're switching it into body fat, just like those hybrid cars where you go from gas to electric, right? So it's using food and then boom, it goes, okay, I have no food coming in. I need to switch over now into body fat. And then it goes, whoa, I have like 500,000 calories of body fat here. So why do I need to cut cut it down. And the point is that it doesn't because assuming if you have no body fat, of course it's a problem. But for people who have adequate stores of body fat, which is most of us, and truthfully most people do it for weight loss, too much body fat, then what happens is that there's so much there, why wouldn't you use it? Because it's a fuel source. That's all it is. That's the way you have to look at the body fat. If you're eating all the time, you can never use your body fat. because your insulin's here, your insulin's high, you're using food. Then you get hungry, so you eat some more, right? You have a snack, you have a low-fat muffin, you stay here. You can only burn food. All that stuff over there, those 500,000 calories of body fat are completely inaccessible for your body. So if you simply dial it down like this and say, okay, instead of 2,000 calories, I'm going to eat 1,500, but I'm going to eat 10 times a day, keeping myself here. Now you only have 1500 coming in. You can only burn 1500. You can't access that. If you go to zero, you go boom, and then your body burns the full 2000. So they did a study, for example, where they took people and fasted them for four days and measured how many calories they're using. They also measure their VO2, which, as you know, is something that it's a measure of how much cellular work your body is doing. and what they found, so they measured the metabolic rate at time zero, then they measured it at four days of zero food, and they were burning 10% more calories than they were per day than they were when they were eating. The VO2 was 10% higher. You're doing more work. Your body is actually not shutting down, it's revving itself up. And again, there's a good physiologic reason for that, and we know that when insulin goes down, when you switch yourself into this sort mode that you're burning fat, other hormones go up including your sympathetic nervous system, which is your noradrenaline. So you're actually pumping your body up. The reason for that is sort of again, it's a survival response. So imagine again we're cave man and it's winter and there's no food. So if you don't eat for two days and you get weaker, you're never.

Going to die again.

You're going to die because every day is going to be harder, you're going to circle the drain. so our body's just not that stupid, right? So what they do is that your body says, okay, there's no food coming in. Boom. I'm gonna switch you over to body fat, and then I'm gonna pump you up so that you have energy.

You go out there, you go kill that woolly mammoth. You're focused, you're clear, you're in the zone, everything.

Exactly. And that's, that's the reason that we actually pump ourselves up. And in the constant, the mental aspects is actually fascinating because people also say, well, I, I have to eat because I have to concentrate. It's like your concentration is actually much higher. when you don't eat. Think about when you had a huge Thanksgiving meal. Well, were you really sharp or did you really want to just lie down on the sofa and watch some football?

Right?

You don't have any sort of focus. But if you think about animals, it's the same thing. Lions, they just eat, they just lounge around. But if you're the hungry wolf, that is not, that is a very dangerous animal because he's focused, he's ready to kill you. Same thing for us. Our level of concentration, our mental ability, mental agility goes up significantly when we're hungry. Like if you think, oh, you're hungry for this, hungry for that, that doesn't mean you're falling down lethargic. It means you're focused. So it's interesting because there is this book a few years ago called Unbroken, which is a biography of this fellow who went to a prisoner of war camp in World War II Japan. and he was talking about starvation and he they were literally starving like there's they eat like almost nothing for the full day. And he's talking about how his his his other prisoners were doing these incredible mental feats. So one guy was reading a book entirely from memory. Another guy learned all of Norwegian in a week. And he so the guy says this is simply the mental clarity of starvation. so it was incredible. It's like it was so widespread, everybody was starving, and they'd see these incredible feats that nobody else in the world could do all the time because your mental ability is ramped up to such a high degree. And then, you know, in the ancient Greece, the ancient mathematician Pythagoras, he would require his students to fast in order to come to his class because otherwise he thought they had no mental agility.

I'll tell you three foods that actually harm the body's health defenses and including the immune system by ratcheting it up inflammation and then lowering the defensive properties.

But also harm to your DNA, also.

Harm your microbiome, also blunt and stun your stem cells.