The Fasting Doctor: “Fasting Cures Obesity!”, This Controversial New Drug Melts Fat, Fasting Fixes Hormones! Skip Breakfast!

**Jason Fung** (0:00)
This calories in, calories out model doesn't work at all.

**SPEAKER_2** (0:03)
If you're trying to lose weight, what you need to do is Dr. Jason Fung, the founder of intermittent fasting, whose influential work could be the key to a healthier and even longer life.

**Jason Fung** (0:14)
Every continent is seeing this increase in obesity, but we put the blame on the individual. The problem is there's something wrong with the message we're giving people, and I can go over a few examples. First of all, exercise is really good in a number of ways. But in terms of weight loss, it's actually a very, very small effect. The whole idea that you need to eat as soon as you get up is just false. We know from twin studies that 70% of your risk of becoming obese is due to genetics, but it doesn't explain why the population became much more obese. And we know that you can't cure obesity by saying eat fewer calories. It's about fixing the hormones that are behind the calories. If you want to lose body fat, you actually need to extend the period of time that you're not eating so you do some intermittent fasting. There's all this data showing that fasting activates the body. It increases your energy and your concentration. A treatment available to everybody for free, and it will be healthier for us.

**Steven Bartlett** (1:13)
So I need some advice then. What does your fast look like? What food should I be giving my body? And in what proportions?

**Jason Fung** (1:19)
The first thing you got to do is...

**Steven Bartlett** (1:23)
I've got to talk to you about these new injections people are getting to lose weight.

**Jason Fung** (1:27)
I think...

**Steven Bartlett** (1:30)
Quick one before i this episode starts. About 75% of people that listent to this podcast on audio platforms Spotify and Apple haven't yet hit the Follow button. If I could ask a favour from çyou, if you've ever enjoyed this podcast, please could you just go and hit that Follow button on your app. It helps this show more than s could possibly s.
The bigger the show gets, the better the guests get.

**Jason Fung** (2:01)
Hey, Steven, how are you?

**Steven Bartlett** (2:03)
I'm really, really good.
This book here, The Obesity Code, Unlocking The Secrets Of Weight Loss, why did you write this book? What was the sort of driving motivation behind committing what must have been a very long part of your life to this subject matter?

**Jason Fung** (2:21)
It was actually a very interesting sort of journey of discovery for me. So I did my training in nephrology, which is kidney disease. So I'm a kidney disease specialist. Then I thought about weight loss sort of very conventionally, sort of calories in, calories out, just watch what you eat sort of thing.
And that's what's taught to all doctors is that it's extremely unhelpful for people. It doesn't work at all. It doesn't work for patients and it doesn't work for doctors even, right? So doctors who want to lose weight, they don't use calories in calories out because it doesn't really work. And we all know this.
Every person has sort of counted their calories and almost all of them failed to succeed. So the whole point was how to get people to lose weight. And so I started to look into the literature and I started to read about it and so on. I got very, very interested in it. And again, I started to become very unhappy with the discussion about calories and calories out because the whole point was that people had this idea that it was energy balance, right? And there's this sort of energy balance equation, which is calories in minus calories out equals body fat, right? Because body fat is a way to store calories.
But that's not a very helpful sort of description of how to approach the problem, right?
The problem is not that people didn't realize that they had to eat fewer calories or increase their calorie expenditure.
The problem was why were they eating more calories than they could expend, right? And it's because the body is being told to store energy, right? That's the way it is. That's why you're taking in more calories or you're storing more calories is because your body has hormones that tell you to store calories. So there's a hormone called insulin, for example. And if you give people insulin, so inject them with insulin, which is a drug for type 2 diabetes, almost everybody gains weight. So if you give somebody insulin, they gain weight. If I gave you insulin, you would gain weight. It has nothing to do with the, you know, your willpower, for example. If I gave you insulin, you would gain weight. Why? Because I'm giving your body the instructions to store energy.