1030 How To Prevent Cancer With Your Food & Fasting w/Jason Fung

“The secret to managing our health is not more surgery or more medicine, it’s less.”Physician, author, and researcher, Dr. Jason Fung joins Lewis on the podcast today! He is known for writing groundbreaking science-based books about diabetes and obesity. He is also the co-founder of The Fasting Method, which is a program to help people lose weight and reverse Type 2 Diabetes naturally with fasting. Dr. Fung says, “The seed of cancer may exist in all of us, but the power to change the soil is in our hands.”Stay tuned for Part 2! For more go to: www.lewishowes.com/1030Check out Jason’s website: www.thefastingmethod.com Read his new book: https://thefastingmethod.com/book/the-cancer-code/ The Wim Hof Experience: Mindset Training, Power Breathing, and Brotherhood: https://link.chtbl.com/910-podA Scientific Guide to Living Longer, Feeling Happier & Eating Healthier with Dr. Rhonda Patrick: https://link.chtbl.com/967-podThe Science of Sleep for Ultimate Success with Shawn Stevenson: https://link.chtbl.com/896-pod Get more from Lewis! Get my New York Times Bestselling book, Make Money Easy! Get The Greatness Mindset audiobook on SpotifyText Lewis AIYouTubeInstagramWebsiteTiktokFacebookX

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Jason Fung?

  The secret to managing all of these things is not more medicine and surgery, it's less. It's actually within our grasp because fasting is free to every single person on earth.

• 0:14Lewis Howes?

  Welcome to the School of Greatness. My name is Lewis Howes, a former pro athlete turned lifestyle entrepreneur. And each week we bring you an inspiring person or message to help you discover how to unlock your inner greatness. Thanks for spending some time with me today. Now let the class begin.

• 0:37Lewis Howes?

  Psychologist Anne Wilson Scheff said, "Good health is not something we can buy. However, it can be extremely valuable savings account." And Deepak Chopra said, "Whether we realize it or not, all of us are responsible for creating the body we live in." And my guest today is physician, author, and researcher Dr. Jason Fung. He's known for writing groundbreaking, science-based books about diabetes and obesity. The Diabetes Code, The Obesity Code, and The Complete Guide to Fasting, where he's challenged the conventional wisdom that diabetics should be treated with insulin. He's also the co-founder of The Fasting Method,

• 1:16Lewis Howes?

  which is the program to help people lose weight and reverse type 2 diabetes naturally with fasting. And in this episode, we dive deep into some of the topics discussed in his new book, The Cancer Code, to learn the new science behind the disease and how our diet and fasting can play a role in managing and even preventing us from getting cancer. And Dr. Jason Fung says, "The seed of cancer may exist in all of us, but the power to change the soil is in our hands." And we had such an incredible conversation that I had to split this into two parts. And in this first episode, we talk about the main causes of cancer, what they are, and if it's even possible to reverse cancer.

• 1:59Lewis Howes?

  This will inspire you, what the biggest benefits are from fasting, why we shouldn't snack all the time, and how this is actually hurting our digestive system and our brain. The food to cut to decrease your risk of cancer, the biggest myths around fasting to lose weight, and if supplements and vitamins are actually bad for us. Make sure to share this with someone who needs to hear it, who you think this will inspire and support their life. And a quick reminder, make sure to click the subscribe button on Apple Podcasts right now to the School of Greatness, as well as leave us a rating and review. And in just a moment, the one and only Dr. Jason Fung.

• 2:41Lewis Howes?

  Welcome everyone to the School of Greatness Podcast. Very excited about our guest today. His name is Jason Fung. And you've got a new book out called The Cancer Code, which I'm very excited to talk about The Cancer Code. And I wanted to start with a question to ask you, what are the main causes of cancer? As it seems like you hear about it more and more recently that so many people are getting cancer, or the early stages of cancer. What are the main causes of cancer?

• 3:08Jason Fung?

  Yeah, that's a great question. And that's something that we've always been trying to deal with. And sometimes some people say, well, we don't know what causes cancer. That's sort of a cop out, because we actually do know a lot about what causes cancer. And these are things that cause cancer are called carcinogens. And the World Health Organization maintains a huge list of these carcinogens. But if you want to break it down into what causes cancer in most people, you can look at the sort of a couple of studies have looked at the sort of percentage contribution of these carcinogens to to cancer. And the biggest one, of course, is tobacco smoke. So that's sort of by far and away, the biggest contributor to cancer

• 3:52Jason Fung?

  at around 35%. And these estimates were from 2015. So it was higher before when more people are smoking. But as a contributor to cancer, it's the biggest. Interestingly, the second biggest, and almost as big, is actually our diet. So it's a huge, huge part of what contributes to cancer in general, and far outstrips of those two are way above any other causes of cancer. So when you worry about things such as radiation, or you know, chemicals, sunscreens, and pesticides, and stuff like that, they do cause cancer.

• 4:34Jason Fung?

  But the contribution in a whole population is very small. So what's interesting about diet is that we we know this from our studies. But what part of the diet actually contributes to cancer? And that's where things sort of bogged down a lot. So initially in the seventies, people talked about fibers. So people thought about, oh, hey, well, you know, maybe if you eat a lot of fiber, what you're going to do is have a lot of big bowel movements and that's going to clean out your bowel and you're not going to get cancer. Turns out that wasn't true. Then the next thought was, hey, maybe it's dietary fat. So if you remember the eighties and nineties, there's this huge movement against fat that, you know, all fat is bad for you.

• 5:19Jason Fung?

  It caused the heart disease and all this sort of stuff, much of which is sort of um been, you know, overturned at this point. But there's this thought, maybe it causes cancer too. Turns out that wasn't true either. Um, then people talked about vitamins. So maybe cancer is like a vitamin deficiency. So we did many, many studies, millions of dollars, decades of research, where we would randomize people to say one group that took a certain vitamin and one group that didn't and see if there's any difference in cancer. So we tested vitamin A, didn't work. Vitamin D, B, didn't work. Folic acid, didn't work. Vitamin C, didn't work. Vitamin D, didn't work. Vitamin E, didn't work. Selenium, didn't work. Uh, omega three fatty acids didn't work.

• 6:04Jason Fung?

  So all of those supplements didn't actually make any difference to the incidence of cancer. Uh, and the, the, so we were sort of stuck at that point in the mid two thousands saying, oh, no, it's the diet, but what part of the diet? And that's when it became sort of more and more clear that this cancer is actually an obesity related disease. So what happened, of course, is that in the seventies, eighties and nineties. People didn't really think about it, but then we had this obesity epidemic, so it became a bigger and bigger problem. So, uh, obesity in, in two thousand and three, when they started to look at the studies, that was the first really definitive studies that said, hey, you know, obesity is actually a huge risk factor,

• 6:48Jason Fung?

  as well as type two diabetes and, and both of those conditions will actually increase your risk of certain types of cancer law. So it really depends on what type of cancer you're talking, like if you're talking lung cancer, obesity plays almost no role in it, right? That's smoking. Uh, or if you have asbestos, which causes mesothelioma, which is a cancer of the lining of the lung. Again, obesity plays no role, but things like breast cancer and colorectal cancer, which are sort of really important, uh, cancers, they actually are obesity related cancers. So that was the sort of big link. And, uh, to this, you know, at this point, the World Health Organization considers thirteen different types of cancer

• 7:31Jason Fung?

  as obesity related cancers, which is huge because from two thousand and three, we didn't even know, like when I went to medical school, nobody thought obesity caused cancer.

• 7:40Lewis Howes?

  Really?

• 7:41Jason Fung?

  It's as, almost as big as smoking. It's a huge, huge thing. So therefore, if you know that, that's super powerful because if you can maintain a normal weight, you're going to reduce, just like stopping smoking, right? You're going to reduce your risk of these types of cancer.

• 7:57Lewis Howes?

  But aren't there a lot of healthy people out there or non-obese people that also get cancer?

• 8:03Jason Fung?

  Absolutely, because there's a lot of different things that go on, and that's what I spend the first half of the book talking about, is how the sort of, uh, cancers develop. So it's not just about obesity, just like you can smoke forever and not get lung cancer, but it raises your risk. So same as-

• 8:20Lewis Howes?

  What, what are the other factors? If you're, say you're, there's people out there, they're super healthy, they're working out, they're eating well, but then they get cancer. They're

• 8:28Jason Fung?

  Yeah.

• 8:29Lewis Howes?

  under fifteen percent body fat, twelve percent body fat. What are those other factors of people getting cancer? Main factors.

• 8:38Jason Fung?

  Yeah, the the rest of it, we actually know very little about. So we need to know more about those because certain things, so smoking and diet are probably your biggest factors. And then there's a whole, there's like a hundred different other risk factors for cancer. These are the other carcinogens that we talk about. But also things such as, you know, background radiation and sun exposure, you know, like if you get too much sun, for example. So there's all sorts of other things and genetics plays a role. But one of the big mistakes I think we made is that we focus so much on the genetics part of it, thinking that, well, this is sort of a random mutation that causes cancer.

• 9:15Jason Fung?

  Not sort of which puts the puts the onus on sort of this random luck sort of idea that it's just bad luck.

• 9:24Lewis Howes?

  My parents had this, my grandparents had this gene, so I have this, I'm gonna get cancer.

• 9:29Jason Fung?

  Yeah, exactly. And some people think that that's sort of a death sentence. Like if you take BRCA, which is a certain type of gene, for example. Uh, so this is the gene that Angelina Jolie, for example, got diagnosed with her. Her her mom had cancer, I think, or, you know, an aunt had cancer. So she got tested and she had the gene. And people think, well, for sure, you're going to get, you know, cancer. But it turns out that if you look at the incidence of cancer, if you have BRCA, if you have that gene, in like, you know, in the thirties and forties and fifties, that risk of breast cancer was like thirty percent compared to sort of like eighty percent in modern day America. So what's the difference, even though you have the same genes, what's the difference between those two situations?

• 10:12Jason Fung?

  And it comes down to the lifestyle. So the point about cancer is that cancer is like a seed. So if you have the genetics, you have the propensity to develop cancer. And this seed of cancer actually exists. In all of our cells, and actually not just all our cells, but in all multicellular animals have that sort of seed of cancer. So what's important then is you can't do anything about the seed, but what you can do something about is the soil. Which is that if you provide a fertile sort of soil for that seed to germinate. Then you are going to increase your risk of developing this cancer and cancer is not a rare disease. I mean, it affects like one in 10 of us, one in eight of us, something like that.

• 10:55Jason Fung?

  So it's something that we really have to think about as we live longer because it is one of these really important things.

• 11:02Lewis Howes?

  It sounds like, you know, in the next 30 to 60 years, if we don't figure out how to reverse this or solve this, or I guess create bad soil for the seed of cancer. By creating healthy habits and other ways, it seems like this is going to accelerate. Where it was 30%, I guess 20, 30 years ago or 50 years ago now, and now it's 80%, I guess it's going to be even more in 20 to 30 years, right?

• 11:26Jason Fung?

  Oh, absolutely. And the, the trend is very clear because if you look at the, uh, you know, the biggest killers of Americans. It's always been heart disease and cancer. So if you go back sort of to the seventies, so 50 years ago, you look at heart disease, number one killer of Americans. That's heart attacks, strokes, that kind of thing. Cancer was a fairly distant second. But the rate of death from heart disease has been improving very, very quickly. And the rate of improvement for cancer has been improving very, very, very slowly.

• 11:59Lewis Howes?

  Why is that?

• 12:00Jason Fung?

  It's, it's because cancer is a very complex disease and the way we think about cancer, we just don't know what it is. So for such a common disease, it's a total mystery why we get this cancer. Because if you think about it, it doesn't make any sense for cancer to develop because it's actually part of us. That is, if you develop breast cancer or colon cancer, for example. That cancer cell was initially derived from our own natural cells. So what, why would it want to do this? That is, if you get cancer, then the cancer grows and then it kills you and it kills itself in the, in.

• 12:42Lewis Howes?

  It kills, yeah.

• 12:43Jason Fung?

  Why would this sort of thing ever develop? It doesn't make any sense from a sort of that, that, looking at it that way, but.

• 12:51Lewis Howes?

  Cause most diseases wanna spread, but they wanna stay alive.

• 12:55Jason Fung?

  Exactly, exactly.

• 12:56Lewis Howes?

  Like coronavirus doesn't wanna kill you necessarily, it wants to be able to spread to affect, infect other people.

• 13:01Jason Fung?

  Exactly, and, and in the, in, you know, if you sort of bystander, it just kills you, you know, along the way. But that's not its primary purpose. So the point about cancer is that we have never sort of understood what this is as a disease. That is, if you look at heart disease, heart disease is caused by blockages in arteries. So we develop all kinds of things. So we develop drugs, we develop blood thinners, we develop, you know, you go in and you use a balloon to open up the artery. Uh, you develop, uh, new technologies such as imaging technologies, you develop ways to monitor patients. So because you know what causes it, because if you don't know what causes something, it's really hard to fix.

• 13:40Jason Fung?

  Like if you have a car and all you hear is a random plank and you don't know what the clanking is from, it's really hard to fix it. Same thing with diseases. If you have a disease like COVID, for example, you know it's a virus. Well, now at least you have somewhere that you can start. That is, okay, it's a virus, let's develop vaccine or let's develop some antiviral drug. But if you have no idea what this disease actually is, then you have nowhere to go. So that's what I talk about is how, how we, how we think about cancer, the paradigm of cancer as a disease, what causes it? You have to first understand what it is. And that's been the real mystery, the medical mystery is what is cancer? And the, the way we look at cancer has changed significantly over the last 10 years.

• 14:24Jason Fung?

  And most people don't even understand that. So it's a very interesting story from that standpoint.

• 14:28Lewis Howes?

  Yeah, it's interesting you mentioned, you know, the, the, the heart disease. Uh, I saw Dr. Stephen Gundry endorse the back of your cancer code book. And he's been on my show a few times and he's a guy who did 10,000 heart surgeries. And realized that like the things that he was doing on the surface level to create temporary relief. People were coming back in because they weren't solving the root problem, which was a lot of it around diet and lifestyle. And that's what I'm hearing you say is that diet is a massive contributor to cultivating the seed of cancer to grow and flourish with the wrong

• 15:04Jason Fung?

  Oh, absolutely.

• 15:05Lewis Howes?

  What is it? Is it possible? Is it possible in your mind to reverse cancer by the right diet and by fasting, which is something you talk about a lot?

• 15:13Jason Fung?

  Oh, yeah, because the thing is that if you like, once you have the cancer, it's really hard because that's sort of like, you know, if you if you don't change the oil in your car, then your car breaks down, then you say, oh, I'm gonna start changing the oil in my car. Well, yeah, that's good, but you need a lot more than that. It's the same thing. Once you actually develop the cancer, then it's really hard to fix from a diet standpoint. You really need the drugs that we've spent, you know, millions and billions of dollars developing over these last thirty years. But in terms of preventing cancer, there's actually no reason why you couldn't because you can look at sort of people who live in a traditional society, for example. So you can take a look at, say, the Inuit or the American Indians sort of before before sort of they became westernized.

• 15:58Jason Fung?

  And or you can look at the African people before they're sort of assimilated into a Western culture. And interestingly, those those peoples were actually considered, some of them were considered immune to cancer. There was so little cancer that they thought that the Inuit, for example, or what used to be called the Eskimos, actually could not get cancer. So the university, Queen's University in Kingston, Ontario, they used to send an expedition up to the Arctic Circle every year to study why these these Inuit couldn't get cancer. Of course, as they became westernized and started eating, you know, sugar and white flour, then they started getting all the same cancers that we did.

• 16:39Jason Fung?

  In Africa, for example, this this fellow by the name of Denis Burkett, who was a sort of a missionary and and doctor, when he got down there, he's like, wow, in my, he was like, look at these, the difference, the the people who live traditionally in Africa.

• 16:56Jason Fung?

  Get no cancer, no colon cancer, but the minute they transition to a Western style civilization with their foods, with their, you know, the whole thing. They actually start to get cancer. You don't find cancer when, when that, so it's, it's, it was called actually a disease of civilization. So all of these diseases, obesity, diabetes and cancer were not found in people living traditionally. So the point is not that, you know, one is that they didn't live as long, but the point is that if you can find and understand what makes it, you know, protective from them, why this sort of soil, like we all have the seed, but the soil was different.

• 17:37Jason Fung?

  What it is about that, if we can understand that, then you can, you can, you can reduce your risk substantially to the point where your, you know, your risk is very low. Um, again, as an example, if you take a Japanese or Chinese woman from Japan or from Shanghai and you move them to San Francisco, within a couple of generations, their risk of breast cancer approximately tripled.

• 18:02Lewis Howes?

  Crazy.

• 18:03Jason Fung?

  So it's crazy, exactly, but that's great hope because.

• 18:08Lewis Howes?

  Know the root of it, then you can go back to a different way of living.

• 18:11Jason Fung?

  Exactly. Because if you can, and remember Shanghai and Japan and so on, they're, they're, you know, modern societies. So if you can understand what it is about the, the diet, about the lifestyle, that's so important. You could actually take that woman in San Francisco and reduce her risk of breast cancer by a third. So that's very, very powerful knowledge.

• 18:34Lewis Howes?

  So what would you say are the, the five foods we must eliminate to support us in preventing cancer? What are those five key things that you're like, oh, and if you can get rid of as much of this as possible, it's going to really support. Your chances.

• 18:50Jason Fung?

  Yeah, I think that's a good question and it's sort of sugar is probably one of the very, very important things that we really need to lower because that really supports it and it gets to how cancer develops. A lot of the refined foods and people talk and the most that we eat, like the one thing we eat more than anything else tends to be refined carbohydrates. So, you know, white bread and that kind of thing. That's probably the most important thing is the sugar and refined grains. Refined, anything is probably bad for you. So, you know, even if you're not talking about carbohydrates, but refined, say oils, you should eat natural oils, like eat, eat foods that are sort of in the

• 19:34Jason Fung?

  natural state and refined meats, like, you know, you know, eating baloney, for example. People talk about meat all the time, but it's like, there's a big difference between baloney and, you know, grass finished beef sort of thing. It's, there's a huge difference because one is jam packed full of chemicals and other crap and one is just beef, right? And people have been eating beef for thousands of years. So, those refined foods are refined carb, but also refined fats and refined proteins. Probably those play a decent role, although the evidence is lower. And then the other thing that is really important, the fifth thing, that's probably very important is likely the frequency that we eat.

• 20:16Jason Fung?

  That is, eating all the time provides that sort of fertile soil. So, to understand why this is, you have to get back to sort of how cancer develops. So, you have to understand that cancer almost develops, evolves almost as a separate species from us. So, when you have a breast cancer cell, for example, it originated from a normal breast cell, but after evolves, it, it, it grows or it doesn't grow depending on growth factors and it's almost a separate species from us. That is, it will grow and it won't, the normal breast cell or a normal lung cell, they will do everything to, you know, play on the team, right? So, they're always supporting the body, your partner, a team player.

• 21:00Jason Fung?

  Those cancer cells are not team players. Basically, they're out for themselves.

• 21:04Lewis Howes?

  They're the enemy.

• 21:05Jason Fung?

  And.

• 21:06Lewis Howes?

  It's the enemy coming to attack you.

• 21:10Jason Fung?

  That's right. It's, it's, it's like the guy who's just trying to pad his stats, you know?

• 21:15Lewis Howes?

  Right.

• 21:16Jason Fung?

  It's like, you should have passed. It's like.

• 21:19Jason Fung?

  But that's the point that this cancer cell now is only interested in its own survival. That is, it will grow and it will grow at the expense of its neighbors. So it will keep growing and it will destroy everything around it. So it will move around, for example, so a breast cancer cell will move around the body. And that's not for the good of the whole body, right? It's for the good of itself. It's trying to spread itself around. So you got to realize that the cancer cell responds as a foreign organism. And it sounds very strange to say, okay, we have this foreign organism, almost like an infection in us. But that's actually how our body sees that cancer. That is, our immune system actually detects, it's a very powerful, you know, it kills stuff.

• 22:04Jason Fung?

  But it's very powerful, so it has to be reined in because you don't want it destroying, you know, normal parts of the body. So it recognizes certain cells as foreign and certain cells itself. And cancers are actually innately seen as foreign cells. So it is a foreign invader almost that has evolved from us. But during the development of this cancer, it will grow or not grow depending on growth signals. So our body has certain nutrient sensors. So nutrient sensors tells our body when food is available. So when you eat, certain hormones like insulin and mTOR will go up. And that tells our body that food is available, we should grow, right? Because you don't want your cells to grow when there's no food, right?

• 22:50Jason Fung?

  It's just natural. If there's no food, you got to get rid of some of those extraneous cells. So if you have, if you're eating all the time and you're always, you're always activating these nutrient sensors. You're actually telling your body, grow, grow, grow, grow. So if you eat six, eight times a day, you're telling your body, your cells in your body, grow, grow, grow, grow, grow. If you. Eat fewer times, like three times a day, or you do intermittent fasting. If you don't eat at all, what you're gonna do is shut down those growth signals. And this cancer will have a more difficult time to grow. So if you grow breast cancer cells in the lab, for example, you can't do it without insulin. It will actually wither up and die.

• 23:34Jason Fung?

  So therefore, if you know that, then you can say, well, if I, and that's one of the secrets of why.

• 23:40Lewis Howes?

  Insulin comes from eating any food, or is this only sugar?

• 23:43Jason Fung?

  Mostly, it's carbohydrates and protein. So, you know, but the nutrient sensors come from different foods. So different foods will activate different nutrient sensors. But the point is that if you don't eat, like fasting, for example, one is you're going to lower your insulin levels, which will, you know, lower the growth, overall growth signaling in our body, which is a good thing for adults. And adults' growth is not good. Generally, you stay the same size. You don't want to be growing too much. Because the, you know, growth, um, high-growth environment, of course, lets the cancer sort of grow out of control. And that was the secret to why vitamins, for example, was not a good thing.

• 24:27Jason Fung?

  Because it's basically growth. It's, it's, it supports growth of cells. And what they found in a lot of studies was when they gave people these vitamin supplements, they actually got more cancer. They didn't get less cancer. They got more cancer. So in fact, it's just like if you spray, spread fertilizer on an empty field. You want the grass to grow, but what grows are a bunch of weeds. Because you've put down all this growth signaling stuff. So therefore, all you get is the weeds. Same in the body.

• 24:57Lewis Howes?

  Are, so are supplements and vitamins bad for us then?

• 25:01Jason Fung?

  Uh, there's no, there's no evidence that it's really bad for you. When you give high doses in these studies, you do get certain ones. So folic acid, for example, and beta carotene, which is a precursor to vitamin A. And those two studies, there is actually a, a suggestion that you actually get more cancer from them. Because in our current situation in North America, most of us are not vitamin deficient. Most of us actually have too much. You actually wanna slow down the growth.

• 25:28Lewis Howes?

  Really?

• 25:29Jason Fung?

  And this is why obesity and type 2 diabetes are so intimately linked with cancer is because both conditions are conditions where we have too much insulin in our body.

• 25:41Lewis Howes?

  So we want to lower insulin overall because insulin is one of the main causes of the fertilizer for cancer to potentially grow.

• 25:51Jason Fung?

  Exactly, and there's several ways to do that. One is to change either the foods that you eat, and that is the sugar, for example, the refined carbohydrates that make up the bulk of our diet. And the other thing is to change the frequency with which you eat, because you can affect both things. So just like if you're, for example, to pay, you know, ten dollars and you pay it every day, it adds up quickly, right? If you have a coffee every day and it's like, you know, five or seven bucks at Starbucks, every day, every day, every day, it adds up. So just like that, it's not just the amount that you're paying, which is not much, but it's the frequency, right? Same thing with the foods. It's not just the amount that you eat or what it is that you eat, it's how often you eat it. So if you're eating now six, eight times a day,

• 26:34Jason Fung?

  well, that's a lot worse if you ate once a day, right? That's just basic math, like you can't get around that. And the problem is, of course, that if you look at how people eat today compared to sort of 1970, it's very different. So in 1970, people ate three times a day, breakfast, lunch, and dinner. No snacks, nobody ate snacks back then.

• 26:56Lewis Howes?

  Now it's a snack culture, like snacking all day.

• 26:59Jason Fung?

  Exactly, and people say it's good for you. People say, oh, you should eat multiple times in the day, six times a day, it's good for you. But nobody in the history of humanity has done that before, because we had work to do, right? It's not like your great-grandparents, you know, working in the factory, they're taking off every two hours to make themselves a little, you know, ham sandwich or something, right? It was like, there's work to do, you eat when you have time. So, you know, in the seventies, it's funny because I always say you have breakfast, lunch, and dinner, and that was it. If you wanted a after-school snack, your mom said, no, you're gonna ruin your dinner. And if you wanted a bedtime snack, she would have said, no, you should have ate more at dinner. Right?

• 27:38Lewis Howes?

  Right, you should have finished your meal.

• 27:39Jason Fung?

  Yeah, exactly. And that was the point, and nobody ate not a lot of desserts and all that. Nowadays, of course, when you look at the studies, people are eating five, six times a day. You even look at schools, it's like, you know, uh, oh, you know, they're gonna have breakfast, then they're gonna have a mid-morning snack, then they're gonna have lunch, then they're gonna have an after-school snack, then they're gonna eat dinner, and then if they play soccer, in between the halves of soccer, parents think that you need to feed them like cookies. It's like, hey, well, you know, I played soccer growing up and nobody chased me around with a bunch of cookies. We had a great time.

• 28:12Lewis Howes?

  Exactly.

• 28:13Jason Fung?

  You didn't need it, right? And but but that's six times a day, every single day, and it's ingrained into us. Um, you know, a few years ago, when my son was, uh, you know, going on a trip or something, the school said, well, you should pack him two snacks. I'm like, why? Why would you wanna give him a bunch of snacks? Like, they're not good for you. But there's this idea now that it is good for you, but you're i- it's it's it's tough because it's.

• 28:39Lewis Howes?

  What is what is snacking do to our body, our brain, uh, our digestion system when we're every couple hours putting something in our mouth? Well, even if it's a few nuts or a fruit or a protein bar, like, what is that doing to our brain and our digestive system?

• 28:55Jason Fung?

  Yeah, and this is the big thing that I've had, and, uh, you know, I talk about this in the obesity code, is because our body really, um, exists in sort of one of two states. 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 eat lunch or dinner, there's way more calories in that meal than you can use right at that point. So you wanna store that. So when you don't eat, which is any time you don't eat is called fasting.

• 29:38Jason Fung?

  So when you fast, that means your insulin is gonna drop, and that's the signal for your body to now start pulling those calories out of storage, right? 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 one or the other. You can't do both at the same time. So if now you say, okay, I'm gonna go.

• 30:11Lewis Howes?

  What I'm eating, I'm storing. I'm not using calories. Is that right? Every time I eat, I will store. I'm not burning body fat.

• 30:19Jason Fung?

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

• 30:28Lewis Howes?

  Don't burn anything off my body. Yeah.

• 30:31Jason Fung?

  Exactly.

• 30:31Lewis Howes?

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

• 30:36Jason Fung?

  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, 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 fourteen hours and forty-five minutes. That's the average. So if you start eating at eight AM, you don't stop till ten forty-five PM. That's on average. That's the average.

• 31:13Lewis Howes?

  Fourteen hours, you mean a fourteen-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 fourteen-hour window.

• 31:22Jason Fung?

  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 six o'clock, you're done. You know, boom, you're, you know, now you shift into using those calories. And your mom would, you 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 mealtimes. Um, 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. Your body, so the high insulin, for example, blocks fat burning.

• 32:07Jason Fung?

  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. Problem, of course, is that there's never a time there's no food, right? Every day is the same, same thing, right? Fourteen hours of, 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 eat within a 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,

• 32:52Jason Fung?

  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 seventies 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 now, you went from twelve o'clock to eight AM, twenty hours.

• 33:25Lewis Howes?

  You look good the next day. You're like a queen, you got a six-pack, it's burning fat.

• 33:30Jason Fung?

  Exactly. And nobody died, nothing bad happens, right? There was nothing wrong with that. And hopefully, you learned your lesson too, right? And, 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, there were periods of time.

• 33:54Lewis Howes?

  We didn't have food every day.

• 33:56Jason Fung?

  Exactly, they they could, 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.

• 34:15Lewis Howes?

  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?

• 34:27Jason Fung?

  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 and go like, you know, I'd wake up literally like five minutes before I left the floor. I brushed my teeth, put on some clothes and rolled out the door. I was, you know, it's just, it's just that the way I was, right? And so I, I, 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.

• 35:12Jason Fung?

  Or it's burning sugar, it's just going to keep doing it, right? There's nothing wrong with it. So, 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, it's, 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

• 35:56Jason Fung?

  major religions, for example, there would be a period of fasting that's sort of. Universal, so you know.

• 36:01Lewis Howes?

  Everyone's doing it, so no one's feeling.

• 36:04Jason Fung?

  Exactly.

• 36:05Lewis Howes?

  Stress when they smell the food and they're like, ah.

• 36:08Jason Fung?

  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, um, 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, uh, longer fast right after because I know, uh, that I can lose that weight very quickly. But that means I can enjoy myself. Like a couple of years ago, I went on a cruise and really ate too much.

• 36:52Jason Fung?

  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 of a 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. And 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?

• 37:26Lewis Howes?

  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 it be four, six, eight hours, which I'm hearing is kind of the, uh, which would be a great standard to have between four and eight hours of a feeding time. Is that right?

• 37:44Jason Fung?

  Yeah. Yeah. I mean, if you want to lose weight, you can do very well, of course, with a sort of standard seventies style, sort of eight AM to six PM, which in a fourteen hour fast, every single night. Remember they're doing eight, for twelve to fourteen hours day, 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 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 a car. Like in the seventies, stuff like that didn't exist. You didn't eat in a meeting, in a boardroom, for example. Now you go to a meeting in a boardroom when.

• 38:22Lewis Howes?

  Food everywhere, donuts.

• 38:23Jason Fung?

  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 uh that's the thing. So you could do very well with that kind of, you know, eight hour eating window, four, ten 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 thirty days. People do that all the time, but.

• 38:55Lewis Howes?

  No, no food.

• 38:56Jason Fung?

  No food, yeah. So if you look, if you think about um fasting, so uh the uh what the amount of energy that you need. So a pound of fat has thirty five hundred calories roughly. If you need about eighteen hundred 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 a hundred pounds overweight, you could go two hundred days. You know, if you want to lose a hundred pounds, you could go two hundred days without eating before you get.

• 39:30Lewis Howes?

  And survive.

• 39:31Jason Fung?

  And survive, exactly.

• 39:32Lewis Howes?

  And be okay.

• 39:33Jason Fung?

  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.

• 39:42Lewis Howes?

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

• 39:44Jason Fung?

  Exactly, so use it.

• 39:46Lewis Howes?

  Does it affect your digestive system? Does it mess with your metabolism if you don't eat after a certain amount of time? And and what happens when you start eating again? Does that affect your, again, your stomach, your intestines, your? Calling metabolism, what's affected there?

• 40:01Jason Fung?

  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 is actually one of the best things you can do for yourself. From both a mental standpoint and a physiologic standpoint, assuming of course you're not malnourished, right? I mean, I'm assuming if you're the average American who's, you know, ten, twenty, thirty pounds overweight. Um, 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 the truth is that you don't. I mean, when you, 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.

• 40:47Jason Fung?

  But the minute you need it, it starts burning muscle, right? Like, why would our body be so stupid? And if it were so stupid, how did we survive, right? And it's like, you know, if you save 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, right? Our body's just the same, it's not that. So you know, and I know, and everybody knows that the way that you build muscle is that you exercise, right? So if you have, uh, 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?

• 41:32Jason Fung?

  I mean, you're confusing two completely different things. Um, 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 a hundred and fifty 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.

• 42:15Jason Fung?

  Your body will maintain its musculature based on what exercises stuff you're using. Um, so another big myth, so muscle burning is one thing. The other big, big myth is people talk about. Is a 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 five hundred calories a day and you'll lose a pound of fat a week. What happens, of course, is that you cut five hundred calories a day. Uh, and then your body quickly reduces the amount of calories it uses by about five hundred calories. So now you're actually not losing any weight. That's what happens all the time because.

• 42:59Lewis Howes?

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

• 43:03Jason Fung?

  Well, it stops burning the 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. Uh, 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 like if you normally make a hundred thousand dollars a year and you spend a hundred thousand dollars a year. Now you make fifty thousand. 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 gonna use less. And that's the natural reaction.

• 43:47Jason Fung?

  It's, it's, it's important because it's a survival response. It cannot do anything different.

• 43:53Lewis Howes?

  So it's almost like, so it's almost like you need to be extreme in your use.

• 43:58Jason Fung?

  Yeah.

• 43:58Lewis Howes?

  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.

• 44:07Jason Fung?

  It doesn't work. And, 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?

• 44:52Jason Fung?

  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, 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, there's, you can only burn food. All that stuff over there, those 500,000 calories of body fat are completely inaccessible for your body.

• 45:37Jason Fung?

  So if you simply dial it down like this and say, okay, instead of 2,000 calories, I'm going to eat 1,500. I'm going to eat 10 times a day, keeping myself here. Now you only have 1,500 coming in, you can only burn 1,500. You can't access that. If you go to zero, you go boom, and then your body burns the full 2,000. 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 measured their VO2, which, uh, 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.

• 46:16Jason Fung?

  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 of, you know, 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 men and it's winter and there's no food.

• 46:58Jason Fung?

  So if you don't eat for two days and you get weaker, you're never gonna eat again. You're gonna die, because every day is gonna be harder, you're gonna circle the drain. So our body is 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.

• 47:21Lewis Howes?

  You're focused, you're clear, you're in the zone, everything.

• 47:24Jason Fung?

  Exactly, and that's, that's the reason that we actually pump ourselves up. And the constant, the, the mental aspects is actually fascinating, because people also say, well, 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 wanna 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 like lounging 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.

• 48:05Jason Fung?

  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 got, 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

• 48:36Lewis Howes?

  Yeah.

• 48:37Jason Fung?

  They eat like almost nothing for the full day. And he's talking about how his, his, uh, his, uh, 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, 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, is ramped up to such a high degree. And then, you know, in the ancient Greece, the ancient mathematician Pythagoras, he would

• 49:18Jason Fung?

  require his students to fast in order to, to come to his class because otherwise he thought they had no mental agility to learn this stuff. And it's like, wow, this is incredible. Completely different than what we were taught. But again, same thing, our body is actually ramping up, ramping up because again, our major advantage over the lions and tigers and bears is really the, uh, is really that, uh, mental, uh, ability.

• 49:44Lewis Howes?

  But isn't there a, isn't there like a period of time in the day for most people where they feel, man, I'm really hungry. Like I can't focus. I can't concentrate because I'm starving. Like I want food now. And it's, it's actually hurting them in focusing. It's almost like a window of time where you have to just deal with that period and then it switches on into, okay, I'm not hungry anymore. I haven't eaten in a day, but I'm not hungry anymore and I'm focused. Isn't there this kind of window of time?

• 50:11Jason Fung?

  There, there absolutely is. So this is why it's important to get, you know, to understand what happens during fasting. So you can prepare for it. So if you look at hunger during fasting, so they've done again, studies where they fast people for 24 hours and they measure a hormone called ghrelin, which is the hunger hormone. The higher it is, the hungrier you are. Turns out that our ghrelin peaks three times a day, breakfast, lunch and dinner. So you get hungry at, you know, twelve o'clock. It's lunchtime, you get hungry. So it's a learned response. The question is, what happens if you don't eat? Does hunger keep going up and up and up? It doesn't. In fact, the ghrelin actually peaks and then it just falls. If you don't eat, it will actually just fall down and it will fall down within a couple of hours

• 50:56Jason Fung?

  right to baseline, which means that your level of hunger at, so at twelve thirty, one o'clock, you're hungry. No question about it. If you don't eat by three, four o'clock, that hunger level is actually the same whether you ate or you didn't eat. What happened? Well, your body simply took the calories it needed from your body fat. You took that meal from your body fat and your hunger went down. So that's really interesting. So if you know that it's a wave, right? You just have to let this sort of wave pass over you. I often tell people, you will get hungry, okay? Don't, don't pretend that you're not, because you will. What you gotta do is prepare for it and say, okay, well, if you get hungry, then you either, there are several things. One, stay busy. You know, keep doing stuff. Don't just think about how hungry you are.

• 51:41Jason Fung?

  So we all have had this where we're, you know, working on some kind of, you know, doing work at work, or if you're doing some kind of, you know, home renovation or something. I did this all the time where I'm like painting, you know, the house or something like that, right? And I'll just power right through because I just wanna get it done. And I'm not hungry at all because I'm so busy. I'm so focused on doing the work that I just forgot about it, right? You see this all the time, you know, people who go to the casino and people who play video games, they just get so engrossed. So that's one strategy. The other strategy is to get something like green tea or coffee that you can drink. By the time you finish in, you know, a big cup of green tea, the hunger will have passed. But you know that it's gonna pass and that's the point. You know it's not gonna get worse and worse and worse. And and and that's how you do it.

• 52:27Jason Fung?

  What's even more interesting, actually, is if you look at multiple day studies where they fast people for three, four, five days. The ghrelin peaks and then after about two days, it starts going down. So by, you know, day two, day three, as you get to day four, day five, the hunger almost completely disappears. It's actually fascinating if you've never done it. So I've done a few of these four or five day fasts. And it's interesting because there's actually no physical sense of hunger. There's a whole lot of, hey, that slice of pizza looks really good. I really wanna eat it.

• 52:59Lewis Howes?

  Right.

• 53:00Jason Fung?

  But there's no actual physical hunger. So if I hadn't seen it, which is hard now, of course, with all the advertising and all this sort of stuff. I would have actually, you know, gone and right by and done it. But the point is that the hunger is something that you have to learn how to deal with. It's not impossible because, again, one of the big objections to people with fasting is that nobody can do it. Like, it'll work, sure, if you don't eat, you'll lose weight, but nobody do it. Well, you know, that literally millions of people throughout history have done this. Look at Ramadan, you look at Yom Kippur, you look at Lent. Like, when people say, okay, we're gonna fast together because our strength is in our togetherness, right? You know, it's Good Friday, we're not gonna eat for this amount of time.

• 53:45Jason Fung?

  Well, that's, that's how people did it, right? They supported each other, there was no food around, somebody's not frying up, you know, his steak while you're trying to fast.

• 53:54Lewis Howes?

  Baking cookies, yeah.

• 53:55Jason Fung?

  Exactly. So that's how you do it, right? You get yourself a supportive community, you know, you figure out something that you really love to do that keeps you active during that time. And and that's how you get through it, right? And and and while you do that, of course, your body uses up the body fats, you're gonna lose weight, it's gonna use up the the blood sugar, which is gonna keep you from becoming diabetic. And uh it's insulin is gonna fall, which is going to reduce your risk of cancer in the long term, as well as those other conditions, obesity and type two diabetes, which puts you at such high risk of cancer in the first place. So you're doing all kinds of good stuff for your body and it's completely free, right?

• 54:38Lewis Howes?

  You don't have to spend money on it, yes.

• 54:40Jason Fung?

  And this is the part that's crazy. It's because if you think about the number of diseases that you can make better, heart attacks, strokes, cancer, diabetes, which is the leading cause of blindness, of kidney disease, of amputations. The, the, the, the secret to managing all of these things is not more medicine and surgery. It's less. It's actually within our grasp because fasting is free to every single person on earth. You can do it literally right now and start right now on the path to getting better. It's just a matter of having that knowledge to do it.

• 55:20Jason Fung?

  The people tell you, oh, you can't do it. You can't do it. It's like, that's not true. We all used to do it, right? If you think about, you know, you know, a community of like, you know, on Yom Kippur, like millions of Jews around the world are doing it, or Ramadan, millions of Muslims are doing it. Or, you know, millions of Catholics are fasting during Good Friday. Like my, my priest used to tell me all the time during Lent, you know, fasting, like that's all he talked about practically. Um, so it's, it's, it's such an incredible tool that we've just sort of forgotten about. And yet has more power than almost anything else to prevent all of the diseases. And we don't have to charge anybody anything. We're not trying to sell anybody anything.

• 56:04Jason Fung?

  We're just trying to tell you, yes, you can do it because if you have too much weight and it's putting you at risk of this cancer. Then let your body burn off that sugar. Let your body burn off that fat.

• 56:15Lewis Howes?

  A couple of months ago, I did a four day fast where I just had water and a black coffee a day. Um, and it felt incredible. First couple of days was challenging, but by day three, I was like, I'm in the zone. And I felt good. I looked younger. I felt healthier. Um, I was doing it more of like, seeing what I could do in my mindset and seeing what it would do for my, you know, kind of cleaning out my system. I just so happened to lose seven and a half pounds. It was burning a lot of excess fat. Um, but I just felt better. I felt more confident. I felt like, oh, I could do something challenging.

• 56:58Lewis Howes?

  Which gave me more strength in my mind. It was a spiritual experience in a lot of ways. And I'm curious, what are the other myths about fasting that people are afraid of that, that you've debunked?

• 57:12Jason Fung?

  I mean, uh, the, the, the point about being healthier is one of these things that people think it's super unhealthy for you. It's actually one of the healthiest things you can do. As long as you're, again, not underweight and you're doing it safely, right? You're not on a bunch of medications that need adjustment and that kind of thing. But there's this whole, uh, recent, um, scientific sort of revolution into this process called autophagy, which has been, uh, you know, very, very topical. People have been going crazy on it because in two thousand and sixteen, one of the Nobel Prizes in Medicine was awarded to one of the early researchers. And what it showed is that when you fast, uh, and you turn down these nutrient sensors, then your body actually starts to activate a process called autophagy.

• 57:57Jason Fung?

  And autophagy, um, is where your body breaks down these sort of subcellular organelles and just gets rid of them, right? It breaks it down and recycles them. And everybody thinks, well, if you're breaking down stuff, that's bad for you, right? You're breaking down protein is bad for you, is good for you because the first thing you need to do whenever you, uh, want to renovate, for example, say you want to renovate your bathroom. The first thing you gotta do is throw out everything in there, right? That avocado green tub has to go, otherwise you can't put in a new tub, right? It's just the way it is, that's just, uh, so your body works the same way. The first thing you have to do is get rid of the old junky old protein. You gotta break it down.

• 58:42Lewis Howes?

  You gotta kill off those cells.

• 58:43Jason Fung?

  Yeah.

• 58:44Lewis Howes?

  You gotta destroy them, rip them off the body and let them, whatever.

• 58:48Jason Fung?

  The stuff you don't need.

• 58:49Lewis Howes?

  Flush out your skin or whatever they do, right?

• 58:51Jason Fung?

  Exactly, the skin proteins, the connective tissue, all of that goes. And it's not like the body knows what it needs and doesn't need. What happens is that everything starts to go and then the stuff you need, like if you're still exercising, your body's like, hey, I still need those muscles, I'm gonna rebuild that. So that's the key that one of the things that activates during fasting is actually growth hormone. So if you fast for twenty four hours, your growth hormone level is like four times what it is. Really? When you're eating, yeah. And it sounds very strange. Why would growth hormone goes up? Well, it's because of this whole process where you want to break down stuff as soon as you start to eat it. You want to rebuild all of it. So the Nobel Prize in Medicine, which is Dr. Osuni, said this is the body's

• 59:33Jason Fung?

  intracellular recycling system. So it's not let's flush out all our old stuff. It's not flush it out and rebuild into new stuff. But if you think about it, that's incredibly powerful because that's the whole process of rejuvenation. Right? Get rid of the old stuff, bring in new stuff. It's like renovating your body, right? So all the cells in your body undergo this process of regeneration that you're not going to get if you are eating all the time. So this is this whole, you know, in, in, in people who are very interested in wellness. A lot of people are looking into this autophagy and so on. And, and, and you get this, this point where you're doing, you know, so you, you've done these longer fasts. It's like, wow, this is, you just feel

• 1:00:14Jason Fung?

  really good about yourself, you know, you're, you're, you're full of energy, right? And, and this is the thing that I thought, thought very strange. When I did my first sort of three or four day fast, it's like, I have a ton of energy, like I could feel like I could do anything. My, my friend who used to work, uh, he's, he's a doctor. And he worked a lot of nights and stuff. He said, it felt like my brain was like on fire. Like I thought I could do anything and everything faster than I could and better than I could ever do it before. Interestingly, another friend of mine who's a cardiologist, so he's a heart specialist, he says, you know, I used to, he played piano for his whole life. And he says, there's always this piece that I couldn't play. And then as soon as I started fasting, I noticed that I could start to do it. Wow. That's incredible.

• 1:00:57Jason Fung?

  Right? And and and the doctors, when I talk to the doctors, they actually instantly see the logic of what I'm talking about because they know the physiology, what happens in the human body. Because what I'm talking about, which is what all the stuff we know about medical physiology is in contrast to all this stuff that people tell you about fasting, which is, oh, you can't do it, and it's dangerous, and it's really bad for you. Whereas the opposite is true, right? It's actually part of a natural cycle, right? It's feeding and fasting, feeding and fasting, right? You don't feed all the time, you don't fast all the time. But we've gone so far into that one thing. So, yeah, I mean, this this whole point of um autophagy is very, very interesting and very topical.

• 1:01:37Jason Fung?

  Uh, if you look at studies of longevity, for example, in in animals, the only thing that really um makes people, makes animals in the lab live longer is caloric restriction. And so even almost a hundred years ago, people were talking about it and saying, well, you can try and restrict your calories, but if you do that day after day after day, it's really hard. So fasting may be a better way to go, which is something they figured out sort of ages ago, because if you look back, that's how people thought of fasting, that people called it a cleanse, uh detoxification, uh, you know, reawakening, spiritual, you know, purification, that kind of thing, right? There's this whole sense of rebirth and something super healthy for you,

• 1:02:23Jason Fung?

  which got turned in the eighties into something really bad for you, right? It's strange how how things work, but without any sort of scientific evidence. And as we've become as a nation more overweight, it becomes even more important. And and and that's just one of these sort of fascinating things. So, you know, it's not like something I just made up. It's like literally the oldest dietary intervention.

• 1:02:49Jason Fung?

  In the books, right? I'm just rediscovering this and trying to tell people, hey, there's a lot of good medical science that tells you this is actually something that is applicable to what we're seeing today in our healthcare. And you can do something like you don't need your doctor, you don't need your dietitian. You can do something about it right now for no money, right? And there's the sciences all there, right? Imagine how much money you could save as a society if we got rid of this problem. And it's like, oh, my God, like the, the, it's mind blowing.

• 1:03:27Lewis Howes?

  Well, I think that's part of the issue is, uh, the reason it's not popular, I guess, is because businesses make a lot of money on medicine, businesses make a lot of money on selling more food, not selling less food. And therefore people want to make more money. And so they have to market their products, they have to market their medicines, they have to market their foods to try to sell more of it, not to say, oh, just have a few of these, just have a couple of cookies a day. No, they want to sell boxes of cookies, right? It's not like they gotta make money. As in their mind, this is a business to be run and we need to sell more, more. It means more people need to eat sugar, refined sugar, breads, all these things, uh, refined oils, refined meats, refined fats, all these things you said that are horrible for us to eat.

• 1:04:13Lewis Howes?

  The company's making them in order for them to survive financially, they need to sell more of these things to us, which is a a challenge.

• 1:04:22Jason Fung?

  It's, it's a real problem because if you look at, say, you know, the doctors and the dietitians, you go to conferences, they're sponsored by Calogs and, you know, the breakfast makers and so on. It's crazy. I was watching the show the other day, one of these, uh, you know, um, TLC shows with like these very heavy women. Anyway, they're trying to lose weight and they're taking these protein shakes. I'm thinking, and, and they couldn't drink it. It was horrible stuff. They tasted really bad, so they spit it out. I'm thinking, somebody's just trying to make a buck on you because you should just drink water. Let your body use the fat and use the protein from your own body. Why would you want to drink two of these protein shakes a day? Except that somebody wants to sell it to you, right?

• 1:05:07Lewis Howes?

  Right.

• 1:05:07Jason Fung?

  You're being played here. You're drinking this horrible, horrible tasting stuff and they're spitting it out. They couldn't take it. It's like, oh, this, the whole thing is so sad because it's like, if you knew, you could simply take nothing at all and be far healthier and save yourself a lot of money. It's, it's a sad, sad sort of state of affairs that we get into.

• 1:05:30Lewis Howes?

  What would you say are the top four or five benefits of fasting then? If we had to recap that part of it, what would you say are the, the top five? I'm hearing it's free.

• 1:05:38Jason Fung?

  Yeah. Yeah, so it's free. That's a huge thing. It's, it, you really, you can add it to any diet because remember that it does not tell you what to eat when you're eating. It only tells you what, the period of time that you're not eating. So whether you're a vegetarian or carnivore or paleo or keto or whatever you want to be, even if you want to eat fast food all day, it doesn't tell you you can't eat fast food. It tells you that during this period of time, don't eat. So you can add it to any diet, which is incredible because now we're pulling on a completely different lever. That is, if you think about weight loss and nutrition in general, there's two levers, right? We always think of the what you're eating, right? Eat more vegetables. That's great. But what if you don't like vegetables, right?

• 1:06:23Jason Fung?

  Well, that lever doesn't work, right? So here's a completely different lever you're talking about. Well, there's this other thing I can do to lose weight or get healthier, right? So you can add it to any diet. Um, it's, it's completely flexible. That is to say, you can do it whenever you want or if you don't want. So if it's Christmas and you do not want to fast for these few days, then you don't have to. If they decide to fast longer after Christmas, then sure, you can do that. That's completely up to you. It's not like you're locked in. You know, the fourth thing is that it's very simple. So if you look at a lot of diets, that is to say, uh, say you're on a paleo diet. It's a great diet, right?

• 1:07:05Jason Fung?

  But it's like, this is paleo and this is paleo and this is not paleo, right? It's complex or keto or whatever you want to be. So it's very difficult for some people to understand. And I've tried to explain sort of these differences because they'll always get confused. And you always get the, is this keto or is this paleo or whatever? Whereas fasting is very simple. It's like you can drink water and tea and herbal tea, say, that's it. Everything else you can't eat, right? So it's very simple to explain to somebody. It makes it very easy for them to follow. Cause it's very black and white. If you ate a peanut, that's not fasting, right? Yes, it's not a big deal, but at the same time, that's not fasting. And then the other thing is that it's powerful, right?

• 1:07:48Jason Fung?

  Cause if you, if you follow any type of a diet, there's always a natural limit. So say here you want to lose weight. And so you say, I'm gonna do a keto diet or a paleo diet or a vegetarian diet. So you do a vegetarian diet and you lose a, you know, a few pounds, but not as much as you want. Well, you can't go more vegetarian than vegetarian.

• 1:08:08Lewis Howes?

  You're already doing it.

• 1:08:10Jason Fung?

  Exactly. So what else are you gonna do? There's nowhere else you're, or you can't go more keto or you can't go more paleo. Whereas there's no actual upper limit to what you can do in terms of fasting. And it's powerful because you're eating zero, which means that it is by definition for weight loss, the most powerful diet there is. Like absolutely, you cannot lose more than that.

• 1:08:34Lewis Howes?

  If you put any calories in your body, no matter what diet you're on, you're not gonna lose as much as if you had zero calories.

• 1:08:40Jason Fung?

  Exactly. So that's the whole thing. It is the most powerful diet. It's the, the, the, the most powerful weapon you have.

• 1:08:49Jason Fung?

  But it's, it's, it's like, okay, well, why would you not want it? Right? If you have a lot of work to do, you want the best tool. That's it, right? This is the best tool. And somehow we said, don't ever use this, right? It's like, why? If you use it, you'll actually get all these other benefits. So it's free, it's available, it's simple. You know, you can do it with any diet and it's powerful. And you actually don't have to stop. You can actually keep going. You can, you know, do a seven day fast and take a little break, do another seven day fast. And, and, and, and you can't go lower than zero. There's no way. It is possible physiologically to go less than zero. So it is the most powerful diet. So there's so many benefits. And yet for, for years, I'll tell you, when I started using it with, with patients in about,

• 1:09:33Jason Fung?

  about seven or eight, seven years ago, maybe it was like the stuff we saw was just incredible. People were like coming off their medications, they were reversing their type two diabetes or losing weight. It's like, you know, all from this simple intervention that is literally the oldest one in the book.

• 1:09:51Lewis Howes?

  Thank you so much for listening to this episode. If you enjoyed it, make sure to spread the message of greatness to a friend, post it on your social media, and also tag me when you're listening to this or watching this online, so I can stay connected to who you are and what you're up to. The next part of this episode is all about the science of intermittent fasting, foods to live longer, and how to reverse type 2 diabetes. I'm excited about this one, as I've been trying to learn more about intermittent fasting for myself and fasting in general. So stay tuned for the next episode, because we dive deep. And if you enjoyed this episode, please leave us a five-star rating and review over on Apple Podcast. Let us know your thoughts, how we can continue to bring great content

• 1:10:34Lewis Howes?

  to you every single week. And if you want inspiration sent to your phone every single week from me, then text the word PODCAST to 614-350-3960. And I want to leave you with this quote from behaviorist Steve Mariboli, who said, "It's up to you today to start making healthy choices. Not choices that are just healthy for your body, but healthy for your mind." I'm so excited to dive into these conversations more on the science of the body, the science of the mind, and how we can take our lives to the next level together. And as always, I want to remind you that you are loved, you are worthy, and you matter. And I'm so grateful for you today. You know what time it is. It's time to go out there and do something great.