Introduction to Dr. Jason Fung
Dr. Eric Westman: Jason, it’s been a few years since we were together at a keto meeting. I’m really thrilled to see your work thriving. Tell me, what’s new? Then we’ll go back to what’s old.
Dr. Jason Fung: It has been a few years. I think it was COVID. We used to get together all the time. We used to see each other a couple of times a year at these meetings at least. With COVID, everything just stopped, so that was unfortunate. In the meantime, I’ve gone back a little bit more to focus on my clinical practice, so that’s where I’ve been putting a lot of energy in. I’m a clinician predominantly, I’m not a researcher; I deal with people. That’s where my passion really lives, so I went back to doing more clinical stuff.
I was trying to help a company called Level Two Health. My goal is to really help people put their type two diabetes into remission and to do it on a larger scale because they’re part of United Health, which can, of course, bring it to a lot of people. I’ve been spending a lot of time doing that, trying to put together a program for people to help. It’s part of United Health and they’re trying to make it more part of their core offerings which I think is very exciting.
Dr. Jason Fung’s Background
Dr. Eric Westman: How did you get started in this?
Dr. Jason Fung: It was sort of a gradual process. Like you, I trained very conventionally and I deal with kidney disease. Over the years, of course, type 2 diabetes has become more and more of a problem. We know that from all our epidemiologic data. There have been more people with type 2 diabetes, which led to more type 2 diabetic kidney disease. And so I was seeing a lot of it, of course, people going on dialysis. If you look at the dialysis population all over North America, it sort of exploded in the last 20 years. What you see is the obesity epidemic from the late ‘70s and then an epidemic of type 2 diabetes happening around the late ‘80s and ‘90s, and then 10 years from that you get all the sequelae or the complications of diabetes including kidney disease. You see the dialysis population – which is end-stage kidney failure – really started to explode in the 2000s and 2010s just as I was starting to practice. I started to see more and more of this and really it is a very unsatisfying thing to treat type 2 diabetes and type 2 diabetic kidney disease.
Dr. Eric Westman: Or “manage it,” rather. Nephrologists can do lots of different things and practice can be done in different ways. What percent of your time was actually at the dialysis centers?
Dr. Jason Fung: Probably 40-50% of my practice is dialysis.
Dr. Eric Westman: Half your daily hours were treating people who had no kidney function anymore?
Dr. Jason Fung: Yeah, hemodialysis and peritoneal dialysis. And, because they’re very sick people they tend to take a lot of time.
The Burden of Dialysis
Dr. Eric Westman: That’s a lot of work. I was in awe of the nephrologists and basically, you’re substituting just about every function the kidney does. Not all, but the idea that an organ fails and then a nephrologist basically has a machine that keeps the kidney function going. What was it like to deal with people who are basically tied to this machine for their lives? Dialysis is not a great situation to have.
Dr. Jason Fung: No, it takes up your whole life, basically. It’s three times a week for hemodialysis, four hours at a time. That’s four hours on the machine, so by the time you include setup, cleanup, getting to the hospital, getting to the clinic, going home, and recovering from it, it’s five to six hours every two days. It’s a significant chunk of people’s lives. On the other hand, prior to dialysis, you died of kidney failure, so it really is a technological marvel. If you think about the major organ systems it’s really the only one where it can go to zero and you can still live. If your heart function goes to zero there’s no machine that will keep you alive.
Dr. Eric Westman: Duke has one of the biggest LVAD programs – electric ventricular assist device. Like you, I’ve been using this method with people who are sick. When the first patient came to me who had no pulse and had a battery pack I was rapidly brought up to speed that there are a lot of ventricular assist device heart failure patients at Duke. There’s no liver substitution. Kidney dialysis is really pretty awesome and it’s hard work.
I have to say, it’s a moneymaker for the system, is it not? How did you then figure out you could stop this from happening?
Dr. Jason Fung: Dialysis is a big imposition on people’s lives, for sure. The problem is that it’s unsatisfying to take somebody, to follow people, because I’m a clinician, they start with their diabetes, and I see them when they get their kidney disease and then it gets worse and worse and worse. Then they go on dialysis. All this time as I treat them, they’re getting worse. That’s not very satisfying as a profession, truthfully.
That’s where I started to really think about why this is happening? What can we do differently? That’s where I started to come to the conclusion that we’re looking at the problem all wrong. We were treating this disease, type 2 diabetes, as if it were a chronic and progressive disease. That’s what they taught. In 2014 in one of my early YouTube videos I did, I said it was one of the biggest lies of type 2 diabetes. If you think back, in 2014, you would go to the American Diabetes Association website and they tell you plain as day that this is a chronic disease which means you’re going to get worse until you die… not a great feeling for the patient, not a great feeling for the physician. The thing is that it was obviously and clearly a lie. There was no possible way it was true because you and I knew and everybody else knew patients who lost weight and their type 2 diabetes would either get better or go away. Everybody knew somebody who was like, “I got diagnosed with type 2 diabetes. I went on Metformin but I got serious about my diet, exercised, lost 20 pounds, got off all my medications, and now my bloodwork is perfect.” Clearly, the clinical experience was that this was a reversible disease. We saw it, we heard it, we knew it.
Everybody knew it and, yet, at the same time, our professional associations, our teachers, our clinicians, and our academics were saying it was irreversible. It’s like what the hell are you talking about? I see it on a daily basis but clearly, we are focused on the wrong thing. We are so focused that this was chronic and progressive and that we should drug the hell out of these people that we forgot to take a look at the people who are actually reversing their disease, because they did, of course.
Modern Care is Medicine Centric
Dr. Eric Westman: Don’t you think a big element of this is that there’s a medication focus in Western medicine? To me, it’s medication care.
Dr. Jason Fung: Yeah, it’s unfortunate, but it’s the way medical education works and medical research works.
Dr. Eric Westman: Because the medical students need to know the mechanism that the drug is going to use. That’s what they put in medical school. This is backward!
Dr. Jason Fung: It’s backwards because if you think about how doctors get taught, a lot of it is unfortunately driven by pharmaceutical money. If you look at any association – American Diabetes Association, American Heart Association, Cancer Association – who funds them? You’ve got this huge list of pharmaceutical companies. If you’re a clinician and you go to a nephrology association meeting, millions of dollars have been pumped in by drug companies, dialysis companies, whatever companies. Therefore, all you’re seeing are speakers that are sponsored by the drug company. There’s nothing wrong with drug companies; I’m not anti-Pharma, but Pharma is focused on selling its drugs. If you have a drug that’s made by company X, that company is going to find a speaker to talk about the disease that that drug treats and why that drug is so good. What you have to do as an association is say, “We’re not going to take any money from anybody; we’re just going to hold our meetings for scientific integrity,” but nobody does that.
Dr. Eric Westman: Back to how you got into this. What drew you toward nephrology?
Dr. Jason Fung: Different specialties have their own personalities. I liked it because I like to think about problems and why they occur because in the end, a lot of kidney disease winds up being dialysis. There’s a lot of physiology, there’s a lot of thinking about stuff, which is that personality of a nephrologist.
Dr. Eric Westman: But then you just weren’t satisfied doing so much dialysis. Tell me more about that.
Dr. Jason Fung: As it became more and more of a problem, type 2 diabetic kidney disease, it was the wrong thing to be doing. If it was a reversible disease compared to a progressive disease, then, of course, we should have been trying to reverse it and prevent people from getting kidney disease as opposed to just managing it or treating it. It’s a totally different mindset. I mean, it’s totally different. The focus was weight loss. That was the key. When you look at all these people who are doing very well, what were they doing? A lot of them wound up losing weight. That was the real key.
It’s one of these things that’s so bloody obvious when you think about it. If you lose weight, your type 2 diabetes often gets better or goes away. So, think about this chain of events. Type 2 diabetic kidney disease is caused by type 2 diabetes. Treatment: got to reverse type 2 diabetes. How do you do that? Well, you’ve got to lose weight. So, the root cause of the whole thing was the weight and you’ve got to focus on that. But how much of my daily life prior to this was focused on getting people to lose weight? The answer was zero percent of my time clinically as a doctor. We’re busy, but it was the wrong work. Think about it. You have this disease that we should have been focused so much – 50 – 70% of the day is focused on type 2 diabetes and its various manifestations and kidney disease, and yet zero of my time was spent thinking about the diets that were important because I was thinking about the drugs that I wanted to put them on. The whole thing was all wrong. It was because of the way I was taught, the way really everybody was taught.
That’s where I started really talking about it, writing about it, and that’s where our paths crossed.
Insulin Resistance
Dr. Eric Westman: What is the cause of insulin resistance?
Dr. Jason Fung: When people say, “What causes type two diabetes?” They say it’s insulin resistance. That term itself refers to the fact that one of the functions of insulin is that it opens up these channels in the cell and allows the glucose in the blood to go into the cell. The cell will now burn it for energy. That’s great. That’s what’s normally supposed to happen. When they look at type 2 diabetes, they see that there’s plenty of glucose in the blood. That’s how you make the diagnosis. The question is, why is there too much glucose in the blood? In type 1 diabetes, there’s no insulin, that’s why. The insulin can’t open up these gates to allow the glucose to go into the cell. Inside, the cell is starving because there’s no glucose, outside in the blood there’s tons. If you think about a restaurant or something and you have the doors locked; inside it’s empty and outside everybody’s waiting around lined up.
In type 2 diabetes, they imagine a similar situation. They said that there’s insulin around, so that’s the difference. In type 1, there’s no insulin. In type 2, there is insulin around. People have the key, they’re trying to open the door, but something’s blocked. The door is not opening, the glucose now cannot get into the cell, and you’re going to get this similar situation where the glucose is piled up outside the cell. The problem with that is that if you think that’s the problem in type 2 diabetes and insulin resistance, you could follow that logically – if inside the cell there’s no glucose, people should be extremely thin, as they are in type 1 diabetes. They should experience internal starvation. They shouldn’t have a big fatty liver because fat is a source of energy, too. It was all wrong because, with type 2 diabetes, of course, you have people who are overweight with big fatty livers, and so on.
There’s a second alternative to thinking about this problem of why there’s so much glucose and insulin outside the cell, and that’s the possibility that that cell is simply overfilled already. If you have a restaurant that’s already packed to capacity, people have already jammed the inside, you open the doors but people still can’t go in because you’ve already got too many people in there. The same thing in a cell; if the cell has way too much glucose, even if you open up the gates with the insulin and say, okay glucose, you can now go in, it can’t because it’s full. Glucose piles up outside and you say, okay, that’s the problem.
If you think about this overflow paradigm of type 2 diabetes, it makes perfect sense. If you have too much glucose in the cell, you’re going to have de novo lipogenesis (making new fat), you’re going to have fatty liver. As the liver fills up with fat it’s going to try and get rid of that fat because it doesn’t want fat, the liver is not a place to store fat. Fat cells are a place to store fat. The liver now tries to shuttle all this extra fat out. You’ve turned the glucose into fat – that’s what de novo lipogenesis is – and you shuttle all this fat out. How do you do that? Well, you do that in VLDL, which are triglyceride-rich particles. Now, you have fatty liver, high blood sugars, and high triglycerides because your VLDL has gone up which lowers your HDL, and low HDL, that means you have abdominal obesity because you’re shuttling all this fat outside, you’ve got high blood glucose, you’ve got high triglycerides, you’ve got low HDL, and you get hypertension because hyperinsulinemia causes hypertension as well. Those five things are actually the five criteria of metabolic syndrome. It’s all caused by the same thing. That’s why those five things all go together with metabolic syndrome because they’re all caused by hyperinsulinemia. You’ve got too much glucose and too much insulin; you’ve got overfilled cells. The liver is just trying to get rid of this excess toxic load and causing the rest of these manifestations. All of metabolic syndrome can be explained by too much glucose, too much insulin – hyperinsulinemia.
Dr. Eric Westman: It’s helpful having Gary Taubes’ book, Rethinking Diabetes to highlight that doctors were using insulin to treat both type 1 and type 2 diabetes, which would cause more damage in people with type 2 diabetes.
Dr. Jason Fung: If you give insulin, the insulin doesn’t get rid of the glucose. What it does is it takes the glucose and just shoves it back into the cell, just like if you have a subway train which is too full, you can keep packing more people in. You get people on the Tokyo subway whose whole job is to just shove people into the subway car. That only makes the problem worse.
Dr. Eric Westman: Historically, Pharma thought if that didn’t work, they would have the kidney leak glucose. People can eat whatever they want and they can pee out the sugar. I didn’t think that was a good idea. What do you think about the Pharma approach?
Dr. Jason Fung: I think the Pharma approach does work; people do leak glucose and their blood glucose comes down. It’s not a perfect solution but on the other hand, it’s not as bad as insulin. It’s levels of badness, if you will. Insulin to me is the worst because you have a situation where your insulin levels are too high and you’re treating it with more insulin, which is insane. It’s like treating a hyperthyroid patient with thyroid pills. You’re making it worse.
Fasting
Dr. Eric Westman: You’re basically sentencing people to a lifetime of diabetes if you’re using insulin. Non-insulin companies are an ally against insulin – philosophically because they make money by using their medications. Let’s get back to diet because you don’t really need all of that although there’s a role for it. How did you get into fasting?
Dr. Jason Fung: I was thinking that the cause of a lot of these problems is hyperinsulinemia, which is too much insulin. If you have too much insulin, you’re basically letting that cell fill up with glucose, you have high levels of insulin, high levels of glucose, and you’re filling up that cell with insulin. At some point, it’s going to fill up and then you can’t put any more glucose in. Hyperinsulinemia, the high insulin, to me, is the big cause of the entire problem. Not just type 2 diabetes but also all metabolic syndrome and obesity.
Think about it: Insulin is a normal hormone, its whole job is to tell you to store fat. That’s really a big job of insulin. It’s not that it’s a bad thing, we need it to survive, obviously, but if it’s too high, like any hormone, it’s bad. If it’s too low, it’s bad. Every single hormone is neither good or bad . It’s just that the level is supposed to be in a certain range and if it goes too high it’s bad. Insulin is a normal hormone so there’s nothing wrong with it, but if it’s in too high a range you’re going to have certain diseases. It’s pretty logical. When you eat, the insulin goes up. As insulin goes up, your body says you should store some of these calories because you’re going to need them later. When insulin goes down – when you go to sleep and you’re not eating, your body still needs energy so at that point insulin goes down – your body now says, “Okay, let me burn some of this energy.” When you eat, the insulin goes up. It says, “Store energy.” When you don’t eat, you go to sleep, it’s a fasting period, and your insulin goes down. Your body says, “All right, let’s pull some of those calories back out and let’s burn them for energy,” and that’s the reason you don’t die in your sleep every single night, because your body has that ability.
If you have a situation where insulin is high all the time and it’s way too high, much higher than normal levels, what’s going to happen is you’re going to store more energy because you basically told your body to store more energy. There are two situations where you have to think why is the insulin too high, diet-wise? Either the foods you’re eating are stimulating a lot of insulin and you have to remember that different foods will stimulate insulin to different degrees. That means that different foods will tell your body to either store that energy or not.
The other thing is over what period of time are you telling that body to store? If it spikes up really high and then goes really low, you’re going to start using it. If it spikes up for one hour of the day and the other 23 hours of the day, it’s low, that one single spike probably doesn’t make an overall big deal of difference because it’s low for the other 23 hours. That’s why I thought the diet is one aspect of hyperinsulinemia but the other aspect is how often you eat. Remember, at this time it was 2014 and people were convinced that you had to eat 10 times a day, that that was absolutely necessary for optimal human health, even though in the past people never ate that way. Why? Because there was not all this processed food. Who’s going to get up, make eggs and bacon in the morning, eat it, and then at 10:30 go and bake a little muffin – don’t you have to work? It was this whole idea that you had to eat constantly, but in the past nobody did that. In the 1800s, who was snacking constantly? Nobody. Everybody had to work in the fields, everybody had to go to the factories. Nobody’s stopping in the middle of the day to constantly eat.
Even if you think back to the ‘70s, nobody was eating at their desk. If you were hungry at 4 o’clock after school, your mom says “No, you’re going to ruin your dinner.” There were no after-school snacks; you just sucked it up until dinner time. You ate at those specific times because people were just too busy doing other things.
It’s not just the amount that you eat, it’s also what you eat. Different foods have different insulin effects. If you’re not letting your body drop into low insulin levels, you’re not burning those calories.
Dr. Eric Westman: Since food raises insulin, was your logic to cut it all out?
Dr. Jason Fung: I thought what if you cut it all out; that’s the logical conclusion as to how far to take it. Then I thought, what a bad idea. Everybody knew that you had to eat 10 times a day, which was given in 2013/2014. I thought about it. I think that it’s really bad to not eat for 14-16 hours of the day, but wait a second: as a physician I tell people to do that all the time. If you come into the hospital, you have pancreatitis, you don’t eat. If you’re pre-op, you don’t eat, if you’re post-op, you don’t eat. If you go for a colonoscopy, you don’t eat. Even if you did fasting bloodwork, you had to fast, if you did an ultrasound you had to fast. Literally every working day, I’m telling people to fast for their bloodwork, ultrasound, or colonoscopy. If you just had surgery, you can’t eat. Literally every day, I’m telling people four, five, six times a day not to eat. Did anything really bad happen to their metabolism? No, not at all.
It was very funny because I remember at that time, I was taking care of a lot of post-ICU patients and people in the ICU were very sick. They’d have pneumonia or something, they’d be intubated and you couldn’t feed them for different reasons. They’d go in on a hundred units of insulin and they come out and they’d be on nothing; no insulin. Their diabetes was completely gone because their sugars were completely normal and then they started eating again but their sugars were still normal. I was like whoa, what happened? Why did they go in there with so many insulin requirements and come out with none? And, it wasn’t happening once or twice. I’d see it at least once or twice a month. I’d see these cases and think, “Very interesting. What could be the cause of it?” That’s when I started to think, “What’s the mechanism?” That’s when I started to realize that fasting is not that bad for you.In fact, it can be very good for you in situations where you have too much glucose.
Dr. Eric Westman: I had the great fortune of going around with Adapt Your Life, my company, and doing Saturday morning events. There would be 300-350 people there pre-pandemic. I would ask “How many of you have ever gone a day without eating?” Nobody. “And how many of you have ever seen someone else go a day without eating?” Maybe a few hands. In the hospital, we saw it all the time. People were too sick to eat. The common experience is that we’ve always eaten all the time and you’re telling people not to. That seems weird!
Dr. Jason Fung: It was very weird. I went back into the literature and thought, “What’s so bad about not eating for 16, 18, 20, 24 hours, even up to several days?” When you go back into the literature, you quickly find that there was actually nothing wrong.
Dr. Eric Westman: There should be all these studies showing people dying left and right.
Dr. Jason Fung: There were a few in the ‘60s, actually, but they were crazy. These studies were crazy. In the ’60s, there were no research ethics boards. They did crazy stuff. There were a few people who took people who were pretty skinny already and then fasted them for 30 days or something like that. That’s ridiculous. I remember reading one study with nine patients, or something like that and they fasted them for nine or ten days. These are skinny people. They didn’t have a lot of obese people. They’d fast them with nothing to eat at all. Then, they gave them a big slug of IV insulin. Why?! They just wanted to see what would happen!
Dr. Eric Westman: That reminds me of Ancel Keys. He is seen as one of the evil people in this story. He did the starvation studies where the idea was, what do you do when someone’s been in a concentration camp, post-World War II and the refeeding is an issue? That study probably gave starvation a bad name.
Dr. Jason Fung: If you read the Biology of Human Starvation, which is the study he wound up publishing in the ‘50s, the diet was 1540 calories, which is a very low-fat diet because they wanted to replicate what was available in post-World War II Europe. They had high starch because, remember, protein and fat are relatively expensive. Meat is expensive, fat is expensive. People were eating turnips and all this other stuff. It was a low-fat diet, 1,540 calories a day, which was actually 40% less than the Americans were eating at that time. That’s what most experts prescribed for decades. You’re supposed to cut 500 calories. You were supposed to eat 2,000 calories, you’re supposed to cut it down to 1,500 and cut the fat. That starvation study showed how bad it really was, which was actually what we had been taught to prescribe for decades and decades. And then we wondered why everybody was going crazy on these diets and it wasn’t working. Well, we proved it 60 years ago.
Influences From Religious Fasting
Dr. Eric Westman: You started incorporating the idea that other cultures or religions fast. What have you learned?
Dr. Jason Fung: That’s what’s very interesting because, ultimately, people have been fasting for thousands of years. If you look at any major religion, they all have traditions of fasting. If fasting was truly so bad for us, we should have figured that out some time in the past. We wouldn’t have survived.
Your body has this ability to store energy, which is calories. You can store it as glucose, you can store it as glycogen in the liver, or you can store it as body fat. Either way, those are the body’s ways of storing energy. If you don’t eat, your body is going to use either glucose or body fat because that’s a source of energy. And that is precisely the reason you have body fat. It’s not there for looks; it’s there for you as a source of energy in case you don’t eat. You’re simply providing the situation where your body needs to go into its stores and burn off the glucose. If you’re a type 2 diabetic and you have too much glucose, your body is going to burn it off. And that’s good. You’re not going to need those drugs.
I have no problem with those drugs. I prescribe a lot of drugs as a physician, but you can do it completely naturally for no cost. If you have too much body fat, you can do exactly the same thing and force your energy to use its stored sources. In other words, what you’re trying to do is force your body to eat its own glucose and eat its own fat that is already stored away. That’s natural.
Dr. Eric Westman: Historically, how long did people fast? Was it just daytime fasting, total fasting, or water fasting?
Dr. Jason Fung: It’s all different. You have different fasting traditions. You have the Greek Orthodox, who have different fasts and sometimes what they call fasting is actually they don’t eat meat, for example. They’re cutting at one source. You have the Muslims who do Ramadan and they won’t eat from sunup to sundown. It’s probably like 12-16 hours. They do a dry fasting, which means that they don’t drink water either. You have Buddhists who will often not eat after noon time until the next day. They’re going for 18 hours or something like that. So you have all different fasting traditions. Some Jews have their fasting tradition on Yom Kippur. During Lent, there are certain fasting traditions and people do different things. Sometimes it’s only fish on Friday. That was not a form of fasting, but a form of dietary alterations on those days. There are different fasting traditions. I go to a Catholic church and every time around Easter, they talk all about fasting. The passages they read are all about fasting, which I always thought was very funny because at the time, 2013, 2014, when everybody said, “Fasting is the worst thing you could possibly do to your body,” all the time I’m in church, I’m listening to the pastor talk about fasting just a week, why you should fast, how it’s good for you, and how it cleanses you.
It’s interesting because when you think about fasting, it was always tied into this idea of it being a very healthy tradition. It wasn’t fun. Nobody liked it. It wasn’t for a good time, but it was something that you should do on a regular basis to keep you healthy. Even the word “breakfast” means the meal that breaks your fast. What it implies is that you have to fast in order to break your fast. You can’t be eating all the time.
The Optimal Diet
Dr. Eric Westman: What is the optimal diet?
Dr. Jason Fung: Cutting down refined carbohydrates is probably very important. If you look at weight loss, people who need to lose weight or people who have type 2 diabetes, you have a situation where your insulin levels are too high. When you measure the insulin levels of people who are obese, they are definitely higher than normal. It’s the same with type 2 diabetes. It’s actually a spectrum. You have normal people whose insulin levels are sort of normal, then obesity where they’re high, and then pre-diabetes where they’re higher, and then type 2 diabetes where they’re even higher than that. We know that hyperinsulinemia, obesity, and type 2 diabetes all go together. If your insulin levels are high, you should eat foods that don’t raise your insulin level so much. I’m not sure why it’s so controversial.
Dr. Eric Westman: Most of us don’t get much nutrition training.
Dr. Jason Fung: It’s not that hard to understand when you actually break it down. With type 2 diabetes, you have too much glucose. “Sugar” is a nebulous term because it can include fructose, which is a different type of sugar. If we just talk about glucose, it’s blood sugar. Fructose doesn’t circulate freely in the blood. Blood sugar is blood glucose. If you look at carbs – bread, rice, and potatoes – they’re all glucose. In nature, nothing is 100% something, it’s all a mix of stuff. If you look at carbohydrates, like highly refined wheat, and take out all the fat and protein, you’re left with 100% carbohydrate, which is the flour. That flour is basically all glucose. It’s arranged in chains, and you can go down through the biochemistry. It’s arranged in two forms, amylose and amylopectin, and those are broken down into glucose. It’s all just glucose.
If your blood glucose is too high, as in, you have type 2 diabetes, why would you want to eat all that glucose? You could eat an egg, which has zero glucose. It has protein, which is an amino acid. It has fats, but no glucose.
Dr. Eric Westman: I can teach this and people don’t believe me. They want me to prescribe them a glucometer. They’ll pay $100 a month to test out what I’m saying.
Dr. Jason Fung: It’s because the message is so muddied by all the other people out there, including a lot of doctors who say, “You should eat low-fat and lots of carbs.” It’s all about the calories. This bugs me the most. It’s all about the calories. It’s all about the energy, it’s all the same. How is it the same?
Dr. Eric Westman: What should I eat in that one meal a day then? Have you figured it out?
Dr. Jason Fung: You have to take your own situation. This is where I think it’s very strange because if you have a situation where somebody is type 2 diabetic or overweight and wants to lose weight, then cutting down the carbohydrates and intermittent fasting makes a lot of sense. On the other side, you have somebody who’s not overweight, healthy, exercises a lot, and then they go, “Oh, well, I really need to go low-carb and do fasting.” I think “Why? Your insulin levels are not high, why are you trying to lower them?” There’s no reason for you to.
Dr. Eric Westman: There’s emerging science there for anti-inflammatory effects. Do you have a carb level? I think in terms of total grams of carbs per day.
Dr. Jason Fung: I think about total grams, too. I usually try to tell people to stay under 50 grams. I’m probably a little bit more lenient than you.
Dr. Eric Westman: In our book, End Your Carb Confusion, we have 20, 50, and 150 grams – the classic three-tier carb intake. It’s to accommodate the metabolism of different people. The context matters. For diabetes, under 50 grams of total carbs per day seems quite reasonable, especially if you’re eating one meal a day or intermittent fasting. Is that reducing the calories as well?
Dr. Jason Fung: It should. The idea is not to take the three meals that you would have eaten and cram them all into a single meal. That’s not the idea of intermittent fasting. It’s hard to do. The idea is that if you normally eat three meals a day and you drop one of them, the other one should stay the same or as close to the same as you can get it. Say you normally eat breakfast, lunch, and dinner, then you drop dinner and lunch, and you’re only eating breakfast. You should eat as normally as possible because during lunch and during dinner, you’re trying to force your body to eat the glucose that’s in your blood or eat the body fat that’s on your body so that you lose glucose so you can reverse type 2 diabetes or you lose fat so you can lose body fat. If you simply eat more for a meal than you usually eat, you might do okay because it’s really hard to eat a single giant meal compared to three. When you space them out, it’s easier. The more often you eat, the more likely you are to eat more in total.
Dr. Eric Westman: Would it be reasonable then for someone in my clinic, my world, my patients that if they can’t wrap their head around a strict, perfect keto diet, if they incorporate the intermittent fasting, the one meal a day idea and have a little carb just that one time a day if they can stick to it, they might get the metabolic effects?
Dr. Jason Fung: Yeah. The whole idea is that they’re part of the equation. If cutting the carbs doesn’t work for you for whatever reason – diets, preferences, whatever, then you can alter another part. If you can’t cut the carbs very well, then you can tinker with the fasting. They’re all different things. If you do have carbs, maybe there’s something else you can do, change the types of carbs so that they’re not so refined. There are different ways to change it so that it works out for you.
Cutting out snacks is a giant one because snacks weren’t part of the regular diet of people until the last 30, 40, or 50 years. That part can be moved back because that’s more of a societal thing. That was one of the big things I fought against in 2013 and 2014 – the idea that we needed to snack constantly to lose weight. I’m like, “How? How do you expect that to work?”
Legal Challenges
Dr. Eric Westman: No one has been sued in the U.S. for doing this, despite people saying that it’s not true, but other doctors in other countries have been in hot water from their professional standards boards. We had Tim Noakes in South Africa and Gary Fettke in Australia. Have you ever gotten into any entanglements?
Dr. Jason Fung: Luckily, I haven’t. Part of it is because I think I focused a lot on the science and education rather than saying, “You must do this.” I think Tim Noakes and Gary Fettke both were unfairly targeted, truthfully. It was a total witch hunt. Those stories are awful.
Parting Words
Dr. Eric Westman: That’s good to hear. What would you want doctors to know?
Dr. Jason Fung: I think I would want them to know, for type 2 diabetes, even if you look at the American Diabetes Association nutrition guidelines, they’ve actually completely changed. Low-carb, cutting down the carbs, used to be this very fringe way to do things. If you actually read the guidelines, they state that the low-carb diet or cutting down the carbs is the diet with the most evidence – not Mediterranean, not low-fat, not low calorie, it’s low carb that has the most evidence of any diet that has been scientifically studied for improving type 2 diabetes.
For fasting, there’s not a lot of data, which is true, but they do say that this is a very promising area; it may be a way to achieve your nutritional goals without counting calories or counting carbs. At least, that’s a pretty good endorsement.
Dr. Eric Westman: Any final thoughts for my patients?
Dr. Jason Fung: The most important thing to remember is type 2 diabetes is a reversible disease. It all changed around 2021. That’s when the ADA first published criteria for remission which says remission is possible. The reason we struggle is because as physicians, we’ve been taught for two, three, four decades that it’s chronic and progressive. They’ve only changed it since 2021. That’s like two and a half years ago. That’s why nobody says it. That’s why none of the dietitians know it, none of the nurses know it, none of the educators know it because it’s relatively new.
The goal of type 2 diabetes care is not management, as you say, it’s reversing it. You should try to not have this disease. Of the diets you want to try, low-carb has the most scientific evidence and intermittent fasting can be a useful tool. That’s basically straight out of ADA and nothing you will hear anywhere else. That’s great information because it’s immediately actionable for people to say, okay, I get it, my blood glucose is high, and I don’t want to be eating a lot of glucose, it makes perfect sense to me. The foods that raise my blood glucose I shouldn’t be eating so many of those, that makes perfect and now the science is behind you. The Diabetes Association is behind you.
Now, we have to figure out how to make it easy for people and get them to follow. At least the task of the science of it is relatively moving in that direction.
Watch the full video here.