Want a natural way to lose weight, prevent/reverse disease, and improve your health? We have the tool for you! In this episode Dr. Lauren Lattanza chats with Dr. Jason Fung, a Canadian nephrologist and a world-leading expert on intermittent fasting and low-carb nutrition plans. They cover how fasting can impact the storage hormone insulin, and how balancing it out can allow your body to release weight and avoid disease. Tune in for health information everyone can utilize!
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Dr. Jason Fung Shares How Fasting Fights Insulin Resistance And Obesity
We have an excellent guest for you. We are bringing to you Dr. Jason Fung, MD, an astrologist who has become a world-leading expert on intermittent fasting and low carb dieting, especially in treating people with Type 2 diabetes. He has become incredibly multi-faceted and now is a best-selling author having written The Obesity Code, The Complete Guide To Fasting, The Diabetes Code, The Longevity Solution, Life in the Fasting Lane, and The PCOS Plan.
I know that there are cookbooks to go along with all of these, so there is so much information that he has brought to us. I have personally been a fan and follower of his work for years now, and I’m delighted to bring him to our audience. He knows that surgeries and pharmaceuticals are not solving chronic medical issues and has a lot of great information on his website at TheFastingMethod.com.
Welcome to our show, Dr. Jason Fung.
Thanks for having me here.
If we could get a little bit of background information on you because not all nephrologists practice the way you do or see things the way that you do, how did your journey in the medical field begin?
I was trained at UCLA for Nephrology and I practiced years of my career but as things went on, I started to be a little bit dissatisfied with how things went because we are seeing a lot of issues with Type 2 diabetes predominantly because that is a big cause of kidney disease and things were not getting better. There are more people who are developing Type 2 diabetes, which means more people are getting kidney disease, which is why I was seeing them.
When I started to think about it, the way we were treating it was all wrong because everybody at that time was saying that Type 2 diabetes was a chronic and progressive disease. That was not true because everybody, doctors, and patients knew that if you lost weight, your diabetes would either get better or go away.
This idea that it was chronic and progressive was simply a lie. It was probably a lie that physicians, we told ourselves so that we would feel better about not getting them better but nevertheless, when you tell people that it is chronic and progressive, and there is nothing you can do, you are not telling the truth and you are not giving the people that want to make a change.
You are not doing that many favors. That is where I started to get interested in the topic of how to lose weight because it was a huge issue for any medical disease. It is well-known that it is a risk factor for heart disease, strokes, cancers, diabetes, and joint pain. Many different chronic diseases are related to weight, and yet, as physicians, we had given up that field.
Find the balance between feeding and fasting because we had gone so far in the other direction where we had been telling people you have to eat all the time.
We gave it up to Weight Watchers and Jenny Craig thing. It was very strange to me why we would do that because it was an important determinant of health and we did not have any idea what to do with it. I think that a lot of it was due to our training. That is where I started to talk about weight loss and how a lot of the stuff that we had been advocating, which is looking at calories, counting calories, and so on. All this stuff that we had been saying, which is getting an app, doing more exercise, and counting your calories. It was not working.
No matter what we thought about it, it was not doing what it was supposed to do. That is why I started talking about other things, low carbohydrate diets and also intermittent fasting, which is something that had been severely in disrepute by the time I had started using it many years now. Of course, when I started using it, literally everybody thought I was insane.
Everybody knew that it was the worst thing you could possibly do to your body. If you skip breakfast, you would die and all this stuff. It was quite hysterical because when I started to look at the physiology and the literature, it was clear that there was nothing wrong with it. If you have excess body fat, it is a way for your body to store excess calories. That is what you do.
If you eat, you take in calories. If you have too many of them, you have to store them somewhere, so you store them as body fat. If you want to use it, then obviously, fasting is a way that you are not going to eat anything, your body will simply take those calories out of storage, and then you will use them. Nothing bad happens in between because that is literally the reason you have body fat.
It is not there for looks. It is there for you as a store of calories. To set up a condition fasting where your body is able to use it is not bad. It is actually very good. It turns out there is a lot of good side effects and ide benefits of fasting, including Type 2 diabetes. For example, if you do not eat, your body will use up some glucose because it is a source of energy. If you are using glucose, then that is a good thing because your body has too much glucose.
It is not very difficult to understand. It was quite striking because as I started to use this and talk about it, some people were getting incredible results. They were coming off their medications or diabetes was reversing. It was incredible losing weight. That is when I started to talk about it a lot more because there is such hysterical, anti fasting sentiment at that time. It has obviously changed. I wrote The Obesity Code and it was released in 2016. At that time, there was a lot of hysteria around it.
I would imagine working in nephrology. As you said, you are seeing these diabetic patients that are at the end of the road. It is like, “Now they have got this chronic kidney disease.” You have this wealth of information saying otherwise that intermittent fasting and having these periods of caloric deficit is what is going to help you. Clinically, it is the one that wants to implement these changes because it is not easy, especially with the insulin resistance and the blood sugar picture that they currently have might be pretty hard to get started. Did you find that a lot of your patients were open to the idea of bringing fasting on?
Luckily, a lot of them had known me for a while and they trusted me that I was going to tell them what was good for them. A lot of them did listen to me. Therefore, they did it. Not everybody did it, of course, because it is not particularly fun but the people who are motivated to do it, they could do it. Certainly, those that did it, most of them, saw some level of success. Keeping it up is a difficult thing in this day and age, especially this was many years ago when everybody else was telling them that they should not do it that I was crazy. It was difficult, although it is gotten better in time.
That is where I started to try, reach out to people, and write more about it than speak at medical conferences talking about the physiology of what happens during fasting and why you should not be afraid of it. Interestingly enough, the physicians immediately saw what I was talking about because they knew the physiology and, in fact, most of them were like, “I used to do this all the time in residency. I did not have time, so I did not eat. I was pretty skinny back then.” A lot of them understood the logic immediately. There is a lot more resistance from the allied health professionals, the people on the internet, and so on. It was considered an extreme diet.
It is funny it got called a fad and all this stuff, which was interesting, again because fasting is not something I made up. It has been around for thousands of years. It is literally the oldest dietary intervention in the book. In fact, it had always been considered to be a healthy thing. You do not do fasting for fun.
You do it because you think it is a healthy way to cleanse your body or care for your body. It is not that you should be doing it all the time but there is a cycle and a balance there between feeding and fasting. That is even in the English language. It is breakfast, the meal that breaks your fast. You have to fast to break your fast.
The idea is that you have to have this balance but of course, the tone now is much better. People are more understanding a bit more accepting of it. That is good. That is mission accomplished in some sense that at least as being seen. To me, it is a tool. You can use it or you cannot use it. If you use it right, you can do a lot of good. If you use it wrong, you can do a lot of harm but in the end, it is a tool and we need all the tools that we need that we can get because it is weight loss and Type 2 diabetes is a serious problem. We need more tools and that is one of the tools.
Having a larger toolbox to wean people off of medications that they did not want to be on are willing to put in the work. When it comes to fasting, is there a schedule that is best for improving insulin resistance? This blood sugar piece is 12 or 18 hours, or a 3-day fast. Is that something that you find that there is a sweet spot?
All of them work. It depends on what it is and what you prefer. Most people do these two very popular ones. One is the 16/8, which is time-restricted eating. You eat for eight hours of the day and you fast for 16 hours. You might eat from 11:00 AM to 7:00 PM or something like that, and then outside of that, you don’t.
That is a very popular schedule and relatively easy to fit on a regular day. The idea is not to pack all that you would normally eat in the eight hours. The idea is to eat normally within eight hours and drop everything else outside of that. You are going to limit the benefit if you take all of your meals that you would normally eat and cram them into one diet meals thing.
That is not the point. The point is to give your body the time that it is going to take the calories out of body fat. If you normally eat 500 calories at breakfast, what you want instead is your body to take those 500 calories out from your breakfast and you to eat a normal lunch and a normal dinner. That is one of the more popular schedules and relatively easy to do. People also go up to the next, most popular as they extended is generally the 24 hour, which is also one meal a day schedule. That is not necessarily done every day. It is done some days and not done some days.
If you eat from breakfast to breakfast, lunch to lunch, or dinner to dinner, that is almost 24 hours of fasting. Again, you do not want to cram a huge giant meal in that one meal. You want to eat regularly. Whatever you would normally eat, you drop the other ones. That is also a very popular schedule, relatively easy to schedule into a normal day as well.
If you do not eat breakfast, then you work through lunch. That is a 24 or 5. That is something that you can also do. You can change it up and you can see what you like and what you do not like. Those are probably the two most popular schedules. Anything goes like you could do 3 or 5 days, 12 or 18 hours, or anything in between. The key is not to be eating constantly that is not what our bodies are supposed to do.
If you don’t eat at all, then your insulin is going to fall. That’s the most powerful way to lower insulin.
Finding something that works for you and that is going to be used consistently, I would think as well.
That is the key because if you follow a schedule that you do not like or it does not fit into your lifestyle, then you are not going to follow it, so that is not going to work for you. You might as well try and find something that is so flexible. You do not even have to follow the same schedule week to week if you do not want to or month-to-month. You can do different things and it will still work. I think that the idea, again, is mostly to find this balance between feeding and fasting because we had gone so far in the other direction where we had been telling people you’ve got to eat all the time.
You need to eat 3 meals, plus 3 snacks. There has never been any data and any studies show that eating 6, 8 or 10 times a day is better for you. In fact, it should be much worse for you because if you think about how the body works when you eat, your insulin goes up, and your body wants to store those calories.
That is what happens because when you are eating dinner, you are going to take more calories than you can use for twenty minutes that you are taking that meal, so you need to store it. When you eat, your body sends hormonal signals to store those calories. That lasts for a few hours because, of course, the food gets held in the stomach and is slowly released into the system.
Even if you eat for twenty minutes, you are in this fed state for a couple of hours because not all of it immediately goes right into your system. When you get into this fast state, then your body again, sends a signal and says, “No more food is coming out. Let’s pull those calories that we stored and pull them back out.” That is amazing.
You do not die in your sleep every single night. Therefore, what you are simply doing is trying to maintain a balance. We had swung so far into the other direction like, “Never skipped breakfast. As soon as you wake up, you’ve got to start stuffing food into your mouth and keep stuffing food into your mouth all through the day. Before you go to bed, stuff more food in your mouth to lose weight.” I’m like, “How does that going to work?” That does not work because you are constantly signaling your body to store energy, not to burn energy. That is the point. You have to get that balance back.
You have mentioned all these different pathways. Your insulin goes up, and then we have got other pathways that are downstream. It is not fat storage but other signals that go off in the body. Now, having written books on insulin, obesity including cancer, and PCOS. What are some central themes that you have seen across the board and these disease states that are at the crux of all of them?
The underlying theme of all of these diseases is as if they are all diseases of basically too much insulin. It is a nutrient sensor so when our body senses that there are nutrients, it has a certain specific pathway and it causes weight gain, obviously. As your body is jamming in all this excess sugar, then you can get too much sugar, which leads to diabetes.
It turns out that excess insulin is also a key factor in PCOS. That is what causes a lot of the symptoms of PCOS and also cancer. If your body has a lot of insulin, it is a very potent growth factor, so it is not causing cancer but it is a contributor to cancer. All of these diseases, obesity, diabetes, PCOS, and cancer, are insulin-related.
Cancer, for example. There are about fourteen cancers that are classified by the World Health Organization as obesity-associated cancers, including breast cancer and colorectal cancer. It plays a role in this hyperinsulinemia and it is an interesting way to look at it because if you say, the underlying theme is that insulin is too high.
The obvious question is, “How are you going to lower it to reduce all of these diseases?” The answer is you can change the foods that you are eating to eat foods that do not stimulate so much insulin, so cutting down a lot of the refined carbohydrates and sugar obviously. The other thing is intermittent fasting. If you do not eat at all, then your insulin is going to fall. That is the most powerful way to lower insulin. Therefore, if you are looking for something to have a bit of oomph, then that is something that you can consider using if you want to.
You mentioned how different macronutrients will trigger different signals in the body and how is it that it is low fat. Bringing it back to the idea of fat diets back in the ‘90s, everything was low fat, so eating all the time and eating low fat. How do low-fat diets get it wrong?
It is because they focused on the calories part of it without focusing on the hormone. Food contains calories, which is the amount of energy. You have to realize that there is something very important, which is the food also contains information. When we eat foods, certain hormones go up depending on the food we eat.
If you eat a slice of bread, insulin will go up. If you eat an egg, insulin won’t go up. It contains instructions as to what to do with those calories. It is very important because if you, all of a sudden, have insulin, which is giving you the signal to store body fat, then you eat those refined carbohydrates, so your body is going to store all that. Therefore, you are going to have a harder time losing weight.
It is not impossible but it is harder. If you eat an egg, for example, then your body does not get that signal to store so much body fat. Therefore your body is going to use those calories as energy. It is going to burn it. Your body has a choice to store it or burn it but which one does it? It depends on the hormonal status of what your body is telling you to do but people have ignored it that people said, “This is calories.”
The important part of looking at it from both a calorie standpoint and a hormonal standpoint is that, for the same number of calories, certain foods are more fattening than others, which is obvious. Your grandmother could have told you like, “If you thought anything different, you are an idiot.” One hundred calories of cookies are very different than 100 calories of broccoli.
There is nothing the same about them but people were all like, “It is all calories.” I was like, “No. That is one part and a very small part of the entire thing.” That is why that whole calorie thing fell apart. We focused on cutting calories, then we focused on cutting fat because fat was very high in calories. We thought it would be healthier because there is this idea that cutting fat would make our hearts better.
It turns out it was completely false. After cutting fat for so long, we started to realize that there is a lot of fats that are very healthy. That is when the 2000s came around and people started talking about healthy fats. Before that, you could not have healthy fat. Olive oil and avocados were fat and bad for you. Nobody ate avocados in the ‘90s. I consider it horrible food.
Calorie restriction is probably the best studied way to increase longevity.
Avocados were the worst food for you, but then nuts were super bad. They are high in fat. Of course, there are a few studies that came out in the 2000s that showed that eating nuts is very healthy for you. Eating the whole dairy is super healthy for you. That is where people started to talk about healthy fats. Now, it is even gone to the point that a lot of the previously unhealthy fats, the saturated fats, even when they are natural like in dairy, for example, are very much considered healthy for you.
The low-fat regime got it really wrong. Some of it is being corrected now. We are talking more about healthy fats. We talked about where we are so much less concerned with the total fat in the diet. The thing about the calories is still there. There is a lot of misconceptions around there. It is not simply the number of calories but it is also made this type of calories, which means the most important thing is like, “What effect does it have on our hormones?”
That is where people got it wrong. Fasting gives you two things. It causes you to lower the number of calories but also changes the hormonal status of your body. That attracts your insulin so that you can now access your stores with body fat. If you do not drop your insulin, you can burn your body fat because your body is signaling to store fat, “Do not burn it.” It is very hard to lose weight when your insulin is high. If we give insulin as a prescription, people gain weight because that is the instructions you are giving the body.
Literally, flip that switch so that that deposition is triggered. When we are talking about fats, people feel more satiated. They have the ability to have these prolonged hours without eating because if they have all of these things from the foods that are necessary, healthy for them, and not trickling this whole hormonal cascade, it is no wonder that we have these hormone associated diseases states coming from insulin or our food where we started in the ‘90s.
I think even some people still do subscribe to the idea of eating five chicken breasts a day to lose weight and still having some hormonal issues when it is like, “Have yourself a grass-fed ribeye and enjoy it.” I think that saturated fats are something I come across a lot in practice that people are resistant to hearing and accepting.
The whole idea is that you want to focus on natural foods. Food such as steak or something grass-fed steak is natural food. Our bodies know what to do with that. It is when you start to create these highly processed foods that you are going to get. You are more likely to get into trouble. That was the big mistake.
The low-fat movement was that the government encouraged food companies to make processed foods that were lower in fat than natural foods, so you had low fat this and that. They were not natural foods. Your bodies did not know what to do with it. Therefore, you probably suffered from it. Obviously, there has been a big change since the ‘70s because obesity rates skyrocketed after that. Part of it was that we encouraged the use of processed foods rather than natural foods. You can eat a varied diet and still be quite healthy but if it is all processed, then it is going to be hard to do.
Largely in food processing, especially when they are removing some of the calories from fat or all bringing the fat down lower, they are replacing it to make it more palatable with sugars and other carbohydrates are going to be something.
The problem is that you are doing something, which is highly concentrated. For example, if you take carbohydrates, all the protein, and the fat, then you grind it off. That is how you do flour. It is a very highly concentrated ultra-pure form of carbohydrate that does not exist in nature. It is like, “It is easy to get into trouble.” It is this whole breast milk thing. In the ‘70s, people thought that we could make bread on breast milk than breast milk. Everybody gave their kids formula because it was better than breast milk. It took a huge coordinated campaign, which most people do not probably remember, which is the breast is best.
That is obvious. It was a huge campaign that took years to change people’s minds back to the fact that breast milk is much healthier than formula use. You use formula if you do not have breast milk. It is not a problem but the breast is best. It took five years of the campaign after campaign to get it through to people. It is the same thing. We think that we can make better food than natural food.
If you eat natural carbohydrates, and there are a number of them, and lots of people have eaten them, we process them into pure carbohydrates, that is better. If you eat protein instead of eating a steak, let’s get this concentrated whey powder that you can throw into a shake. It might be okay for you but it is highly processed in a form that does not exist in nature. You are much more likely to run into problems, drinking a powder shake every day instead of eating food. It is the way it is.
How many studies have now come out about the benefits of breastfeeding since this whole campaign? We have to realize we’ve got to get out of our own way. We cannot be taught nature. We never will. Back to this idea of calorie counting versus calorie restriction. When you have time-restricted eating or you are doing intermittent fasting, you are going to skip those 500 calories from breakfast. It is not the avoidance of some hours. It is the avoidance of some calories as a whole. I know that you talk about longevity if we have this calorie restriction. You talk about this in a group of people in Japan that stopped eating at 80% full and their longevity has shown so much benefit for that.
If you look from the hindmost standpoint, calorie restriction is probably the best-studied way to increase longevity. You notice it in all these animal studies. Rats for example. If you give one group and let them eat as much as they want, and in the other group, you only give them a certain amount, the group that is calorie-restricted lives much longer and there is much healthier.
Keep in mind, again, that it is ultra-processed rat chow that they are getting but the idea is that this is a fairly consistent finding. Even as far as back as the ‘40s, people said, “You can do it two ways. You can either restrict your food every single time.” This is what they do in Okinawa while where there is a tradition of stopping eating when you are 80% full.
They deliberately do this and their longevity is very good. The other way to do it is simply to restrict the number of times that you eat because when you eat, you tend to eat a certain amount. Therefore, you can restrict your calories by taking three meals a day and eating a little less each meal or you can eat two meals a day and eat your full regular meal. Both are adequate strategies but the natural thing for most people to do is to eat until they are full.
That is the way that people generally eat. That is why a lot of people find that intermittent fasting is a much more effective real-life strategy than the other, which is to stop eating all the time. This whole idea of grazing throughout the day is a crazy idea to even think about because it has never been used before. You have never been in a situation in history where people ate all the time. There is work to be done. You cannot be looking for food all the time. You have a job.
The other thing is that when you eat, you are stimulating your appetite. That is why you eat an appetizer. You eat because you are thinking about food, and you are going to start salivating. A little bit of food makes you more hungry. That is what an appetizer does. We have known this for ages. If you eat an appetizer portion of food, and then stop yourself and do this ten times a day, aren’t you making your life hard?
You are going to stimulate your appetite, and then you are not going to eat, then you are going to do it again in two hours, then again and again. Why don’t you simply don’t do that? It is crazy. If you want to lose weight, why don’t you simply cut down the number of times you are eating to two because other times, you can forget about it.
You can certainly do exercise while you’re fasting. Your body knows what to do with itself.
You get hungry. Yes, you will but then you forget about it, do something else, and that is going to pass. It is a much better strategy than constantly having to think about it. Again, years ago, this was conventional wisdom that this is what you needed to do. It was spectacularly unsuccessful. The thing is that you constantly have to think about food.
If you are trying to lose weight, the last thing you want to do is constantly think about food. You are setting yourself up for an incredible failure because you are always thinking, “What am I going to do for my snack? What am I going to do for lunch? What am I going to do for an afternoon snack? What am I going to do for dinner? What am I going to do for my bedtime snack?” Now that you are thinking about food, you are going to want to eat something.
When you do get to eat it, you are going to want to eat more but you have to stop yourself. It does not even make sense from a life standpoint. You are constantly sapping your willpower because you have decided on this strategy that involves deliberately thinking about food, and then not eating until you are full and doing it over and over again in a day. It could work if you want it to but it is not easy.
You are making it a lot harder on yourself and it is something that is already challenging to do out of sight and out of mind. It is probably a better way to do it, so you are having a couple of meals a day or you are doing your intermittent fasting. What I come across as patients try to get this physical activity, they say, “I’m hungry when I exercise.” Do you still suggest that patients would eat to the same fulfillment level? Say 100% is what they eat at any given meal but then they feel hungrier and they are more prone to overeating. Is it still the same level of, “I feel full, so I will stop?”
You can certainly do exercise while you are fasting. Your body knows what to do with itself. We think our body is so stupid but if you are exercising and have not eaten, your body will take the energy it needs from your stores. It is your sugar stores or your fat stores. That is it. Exercise in general overall makes you a little bit more hungry, whether you are fasting or not, that does not change it.
Fasting is a very good strategy to be using because it actually works very well. People generally fast and then they exercise. You exercise on an empty stomach, which is a little bit more effective because then you are making sure that you use the stores of energy that the sugar and the body fat. The other thing that happens is that when we fast, growth hormone and Norepinephrine, so sympathetic tone goes up to it is energy and your body has more energy to do the exercise. The growth hormone is going to make sure that you recover a little bit faster. There are advantages to fasting and exercise.
That goes together. It is a balance there. Of course, you have to have enough calories if you are an athlete but for most people, they have more than enough of that. It does not make much difference in terms of fasting and exercise. You can exercise and fast. It is not a contraindication. It does not stop you from doing it.
That is good information to know. Thank you. I wanted to ask a question that I asked all of our guests on our show. How do you live a healthy lifestyle?
There are a few. There is the weight, which is trying to make sure that you are balanced with not the foods that you eat but also making sure you are not eating all the time. The other thing is to try to exercise as much as you can. It is never very easy to do. There are a lot of other things to managing stress levels and so on. Those are, to me, the most important things.
Getting regular checkups is important for blood pressure and all that thing as well. That is not necessarily diet-related. A lot of people have high blood pressure anyway. Probably, one of the more important things over the years is good control of blood pressure. It has played a big role and decreasing the incidence of heart disease, kidney disease, and all of that things, so make sure they get your blood pressure checked and all that stuff.
I know we see it here in practice pretty regularly. Intermittent fasting does help with the blood pressure coming down.
It is not the only thing that causes high blood pressure but it does play a role in high blood pressure. This so certainly it can because as you, as when you do not eat, insulin falls, insulin tends to make your body retain water. Therefore, your pressure tends to go up. As you start to fast, you can notice a bit of a diarrhetic effect, and then your pressure can come down somewhat. It can be effective for that. We have seen it as well and people coming off their medications for blood pressure.
Tell our readers where they can find more about you, read all of your wonderful books, and all of the incredible information you have put out to the world. I have been a follower for a long time, and I know that we could go on and on but we want to make this a nice, easy, digestible episode for everybody. Where can everybody find out more about you?
I have a YouTube channel. Look under Jason Fung. There is a lot of information there and there are books. You can go to TheFastingMethod.com, where we have some coaching available and a community for fasting, which is often helpful. You can also follow me on Twitter, @DrJasonFung.
Thank you so very much for your time. It has been a great time having you on here. Thank you, everybody, for reading. If you have enjoyed this episode, please leave a comment and let us know what you like. We will catch you next time on another episode.
- The Obesity Code
- The Complete Guide To Fasting
- The Diabetes Code
- The Longevity Solution
- Life in the Fasting Lane
- The PCOS Plan
- Jason Fung – YouTube
- @DrJasonFung – Twitter
About Dr. Jason Fung