All about Intermittent Fasting- From Dr. Jason Fung

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Dr. Jason Fung talks about Intermittent Fasting

If you look back to the 70s, we have large studies that show people ate three meals a day; breakfast, lunch, and dinner. Now, when you do surveys you find that people are eating longer in terms and durations and more frequently. The idea is that if you simply carve out periods of time that you are not eating, then you are going to allow your body to use the energy that’s stored within it, the calories or body fat. You can store the food energy as sugar or body fat. And If you don’t eat then your body is forced to use the sugar, so if you have type 2 diabetes and your sugar is too high, you can simply not eat and allow your body to use that sugar and it will bring it down.
Intermittent Fasting is a hundred percent natural, you are not using medications to do it, and as you do it in a regular basis, you are going to lose weight. Because if you don’t eat you are going to lose weight and as you lose weight your diabetes is going to get better. The obesity problem gets better and that is a huge risk factor for other diseases such as heart disease, cancer, and stroke and all such bad diseases. The whole point is that if you intervene at an early stage to fix these metabolic problems, then you can prevent a lot of diseases down the line. Or if you simply want to lose weight to look good for the summer, then you can do that too because it is 100% natural.
That’s the entire reason that your body has body fat. It’s a store of food energy, you are using the body fat for exactly what it was designed for, and there is nothing unnatural or unhealthy about it. Intermittent Fasting includes all these approaches; you can use different timings, 16 hours fast, or time restricted eating. This is a popular way of doing the intermittent fast. The point is if you shorten the period of time you eat, you are going to naturally use the other times to burn fast. But it doesn’t have to be 16 hours, it could be 24 hours, for example.  That is another popular regimen, called the 1 meal a day. If you eat dinner one day and don’t eat anything till dinner the next day, you’ve got 23 or 24 hrs where you haven’t eaten anything.

When you do shorter periods of fast, typically you do them more frequently. 16 hr fast might be done 6 days a week for example. 24 hr fast might be done 3-4 times a week. And then you can go longer than that if you like. So you can go with the full day. If you eat all three meals today so that you do not eat anything tomorrow, that’s getting towards 36 hours. There are pros and cons for both, of course. There are no real or right answers. Some people like the short fast, some like the long. The key is to get the education, which is to understand what is happening and why you might want to do a shorter one versus a longer one. There is nothing to lock you in. You could do the 16-hour fast one day and the 24-hour fast the next day and nothing at all the day after that. It is very flexible. So you can fit it into your day’s schedule. If one day you have to have lunch, because you are going out for business then you can. And the next day you can skip lunch because you might not have anything to do that day. You might consider that and add that to your fasting period.
So the key is really to get a good understanding of what fasting is, and what to expect when fasting, and these are some of the things we talk about in the book and also at the IDM program. We have a whole program for people to get the education. The other thing that we provide in the IDM program is a community. If you have problems you can talk to people it is just easier to do it as a group because if people around you are fasting, then it is actually much easier to fast. That was the secret behind periods of time like lent, for example, or Ramadan or Yom Kippur. 

All these people have done fasting throughout history, for thousands of years. If everybody is not eating on a day, like Good Friday for example, you don’t feel so out of the ordinary. Yes, you feel hungry sometimes, but everybody else is doing it, so it is easy to go along and that is how these things have been done. It is a very ancient technique, and it is powerful because if you have weight to lose that is making you sick such as type 2 diabetes, now you can use this natural solution to do it yourself and get better. That’s the whole idea of talking about these things. It is to let people take control of their health, and that is if you have a disease that is related to weight or if you have a disease that is related to type 2 diabetes. It causes eye disease and kidney disease and all kinds of diseases. Your options include changing up your diet, but also implementing these periods of fasting which are completely free, in that it is an entirely new way of treating and thinking about the disease.

So there are two types of diabetes: Type 1 and Type 2

Let’s be clear that this is Type 2 diabetes, which is about 90 or 95% of diabetes. Type 1 is not diet-related so changing your diet doesn’t necessarily make it a lot better, but there are ways to tweak it. Type 2 diabetes is the main one when we talk about diabetes, and it is the majority of the cases.
The idea of using diet primarily as your tool is contrary to everything we are taught as doctors.
For example, I went to a lecture one time on diabetes and a very prominent speaker goes “you know diet and lifestyle are the number 1, 2, and 3 choices for the treatment of diabetes, and spent the next 59 minutes out of 60 minutes talking about drugs. The next speaker does the exact same thing. He says you should always treat first with diet and then spoke for the next 59 minutes about drugs.

The way that we are taught is that this is a disease that needs drugs. This is the sort of paradigm that doctors get into. For example, if somebody comes in with an infection you give him antibiotics and they get better.
You don’t think about how to change your diet to fight this bad Toe-Infection. You need drugs. We apply the same paradigm of thinking to the dietary diseases, so we have a dietary disease such as type 2 disease or obesity which everybody knows is related to the diet, and you apply drugs to it and then you think why people aren’t getting better. The answer is obvious if you think about it. It is because you are using drugs to fight a dietary disease. If you just look at it, it is clear that that doesn’t make any sense. you have to change the diet. You have to fix the root cause of the disease, and it doesn’t need drugs, it needs a better diet.
So fix that and the disease goes away, and that’s what we showed in our case series last year that we published. We had three people that we followed and all of them had type 2 diabetes for about 20 plus years and all of them were on very high doses of insulin. We got them all off of insulin and the maximum it took was 18 days. They came off everything and for the next year, they were basically non-diabetic. They have been classified as non-diabetic. For 25 years, they have been treated with medications and they had been told they have type 2 diabetes. Within a month at the most, we had them all classified as non-diabetic. We took them off their medications it was ridiculous how quickly they got better.

What did you have them do doctor, did you have them do the alternative daily diet?

Yeah, we changed their diet, we told them to reduce the sugar in their diet, and to cut down the refined carbohydrates. Then we implemented a 24 hr fasting period, 3 times a week. Three days of the week, instead of eating three meals a day, they would eat one meal a day and that alone reversed the diabetes.
The fact that it works is not really questionable, because if you don’t eat what will happen to your blood sugars? Everybody will tell you they’ll come down. If we know that, why can’t we use that information? The whole problem with type 2 diabetes is that your sugars are too high. Well, here we have a treatment that is going to lower it.
Everybody agrees that it is going to lower it, so let’s just use that, because it is natural and it is free and it is available. Nobody denies that if you don’t eat, you’re going to lose weight. Why don’t we do that? And the reason is we get trapped into thinking we have to eat all the time, even to lose weight and that sounds really stupid because it is really stupid.

We are talking to the amazing Dr. Jason Fung, his books include the obesity code, the complete guide to fasting, and the diabetes code. 

Which book do you think would be a good book to read first?


I think “The Obesity Code” is probably the one to start with. It talks about the science of what causes weight gain and weight loss. Everybody thinks it is about too many calories and it is really not. The human body does not work on calories. It has no way to measure calories. Eating 0-calorie foods doesn’t really work. You have soda or diet soda with artificial sweeteners that have zero calories but switching from regular soda to diet soda just about never causes weight loss.
So it is not about the calories, it is really about the hormonal situation in our body. It is how to fix that.

Diet soda is a no?

It is not any better than regular soda and there are a lot of reasons for that, but basically, it is because you don’t fix the hormonal imbalance that causes the obesity in the first place. The essential idea is that your body can do one of two things with the calories it takes in. it can burn it for energy or it can store it as body fat. Which one it does depends on the hormones. The main hormone we talk about is insulin and when you eat, the insulin goes off and it tells your body to store food energy. That is, our body wants to store food energy when you are eating because when you don’t eat or when you are fasting or when you are sleeping, for example, you are not eating, you need a way to pull that food energy back out your body.
Your body is in one of two states; it is either in the fed state where you are storing food energy or it is in the fasted state when insulin is low and you are burning food energy. That is why you need to cycle them because if you are fed, you have to be fasted, so that’s the normal cycle. That’s why we have the word breakfast. You are supposed to feed then you are supposed to fast and then you are supposed to break that fast.  Now we got rid of all the fasting period and we wonder why people are gaining weight. It is because you are putting in food energy, you are storing it but you are not pulling the energy out, because you eat and eat and eat. All the time you are telling your body to store the food energy which is one of the reasons why intermittent fasting is very effective. Even if you keep the same food and just simply shorten the times that you eat, it works. It works on a different principle entirely than the foods that you eat.
so diet is composed of two main issues: what do you eat but also when you eat it. Most diets only focus on the ‘what you eat’ part of the question, so they miss 50% of it, which is when to eat. So if you eat a very healthy diet, but you are eating constantly, you still may not do very well. You got the ‘what to eat’ right, but you still did not get the ‘when to eat’ right. 

So are there people this doesn’t work with?

There are some people who really shouldn’t be fasting or long fasting. You have got to remember in the 70s, 12-hour fasts were standard. You eat dinner at 7 pm and breakfast at 7 am. That is 12 hours every day, without even thinking about it. 12 hours is sort of a baseline. You can push that to 16 hours. When you start pushing it beyond that, some people are not advised to do this, people who are malnourished, pregnant, breastfeeding, or children. In those states you want them to grow, so it is best not to limit nutrients. So you don’t want to extend it past that.


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