Therapeutic Fasting with Dr. Jason Fung

Hello my friends, welcome to the Biohacker's Podcast where we explore the latest trends, technologies

and insights into optimizing healthspan and human performance.

I'm your host Teemu Arina and today we talk about the benefits of therapeutic fasting.

A powerful strategy for rejuvenation, improving insulin sensitivity, boosting cognitive performance

and enhancing longevity.

Our guest today is Dr. Jason Fung. He is a world-renowned expert on therapeutic fasting

and the co-founder of the Fasting Method.

Dr. Fung's pioneering work on intermittent fasting, time-restricted eating and metabolic health

has helped millions of people around the world to improve their health, lose weight and reverse,

conditions like the type-2 diabetes.

His books, including the Complete Guide to Fasting and the Diabetes Code,

have become international bestsellers.

us his research and insights into therapeutic fasting.

After his presentation, I will summarize top 5 reasons to practice intermittent fasting,

and I will give you the exact protocols on how to perform fasting in a safe way.

I will also introduce one meal a day, which is the method I personally use.

So here is the presentation by Dr. Jason Fung. (Dr. Fung speaking) Okay, thanks for having me here.

This is fantastic. So one of the things about biohacking that's really very seductive is that you can make

a simple lifestyle change and then you get some impressive benefits.

And one of the things in the nutrition space is fasting. And this is not a new idea.

So we're not trying to bring newfangled things to the world.

What we're trying to do is revive these old ideas that are tried and true.

And if you look at fasting, that's been around for many years.

And some very smart people like Benjamin Franklin, who's on the hundred dollar bill, said really

the best of all medicines is resting and fasting.

And to some degree, that's true, especially in this day and age where we're facing this

sort of obesity epidemic, type two diabetes epidemic.

And shortly thereafter, what you can see is about 10 years after that in the 80s,

you can see this steep rise in type 2 diabetes and type 2 diabetes is really

no joke because the thing about type 2 diabetes is that it causes a lot of diseases that we're worried about today. So heart attacks, strokes, also the leading cause of

blindness and nerve damage and kidney failure and all kinds of things. So if you're trying to live

healthy for a long time. Type 2 diabetes and obesity are really going to work against you.

And this was a historic document because prior to that, the government never

really told people what they should and shouldn't eat.

Your mother told you what you should and shouldn't eat.

they thought it was their business.

And in their sort of wisdom, they got a bunch of scientists together and this is

what they decided that we should really eat a lot more carbohydrates.

So rather than the 40 or 40, 50%, they said, really, we should up that to about

55 or 60% and decrease fat to about 30%.

So that was what we got. So if you grew up in the sort of early eighties, like I did, what you got was

the food pyramid, which is this, what we should be eating every day.

And it's been slowly changed. So every five years they change it.

But if you look at the original program on the bottom here, what you should be

eating every day, five to seven servings is bread and pasta and rice and polenta.

So not exactly slimming to most of us thinking about that today, but that's

what we were told to eat and things like an egg, you should eat that once a week.

Maybe that's full of cholesterol and so on.

And that's exactly what we did. So people always like to blame the obesity epidemic on the people,

because they say we told them good advice, but they just didn't listen.

So they got really fat.

But that's not really true, because if you look at what Americans ate and Canadians, we did exactly what they told us.

So butter way down, eggs way down, animal meats way down.

And lots and lots of grains, right? 40% increase in grains and all this low-fat sugar. Yeah, you're going to get rid of this,

you're going to add more of this. So that's exactly what we did. We did what they told us to.

And the result was, of course, a huge obesity epidemic.

So, the other thing that people never really talk about...

a lot more frequently. And to some degree they're tied in, but on the other hand, you can see that

they're eating around, this is the NHANES survey, they're eating about three times a day. So the

big spike here is around two to three times a day breakfast, lunch, dinner. That's the sort of

is we're closer to five or six times a day. So we're eating a lot more frequently. And to some

degree, it's related to the foods that we eat, because if you're eating a lot less butter and

eggs and steak, if you're not eating steak and eggs in the morning, and you're eating a couple

of slices of white bread with jam, you're going to get a lot more hungry. So then you wind up

of eating more frequently.

And then the other thing that we get told all the time is to eat six times a day.

And it's like that advice never came from science.

Nobody ever thought that was a good idea.

It was just because we were hungry. So then we had to eat a muffin at 10 30.

But we're eating a lot more frequently. And that's one of the really big changes of the last sort of quarter century.

And which people, they did is they gave people an app. And they measured how frequently they ate.

So what you can see here is that the 10% of people, so the lowest decile, which is the 10% of people

who ate the least frequently, ate three times a day.

Three is 0.3 times a day.

And the 10% of people that ate the most frequently, ate 10 and a half times a day.

people were just eating breakfast, lunch, and dinner. Now it's breakfast, snack, lunch, snack,

dinner, snacks, sleep. Because that's the only way you can get to ten and a half times per day.

And the median time of eating was 14 hours, 45 minutes, which means that if you ate breakfast at 8am,

somewhere around here, you didn't really stop until 10.45pm.

So basically you're eating the entire time that you're awake.

So that fasting period, which is this time that you should be allowing your body to sort of digest and to use the energy that you've taken in,

no longer exists because all you're doing is putting food and putting all these things into your body

and your body has to somehow deal with that.

And then of course, we wonder why we're getting all fat.

So one of the ways you can hack this of course, is to simply turn back the clock and say,

look, your body really only exists in one of two states.

If you look at the physiology and that's what we're really gonna talk about

in the next little bit, is the physiology of what happens.

And your body can only exist in two states.

You're either putting food in and insulin goes up. So insulin is the hormone that tells your body

to store food energy.

And your body stores it as sugar, as glycogen, or as body fat.

So you're either in the fed state where you're putting food in your mouth,

you're sending your body instructions to store body fat, or you're fasting, insulin falls,

and then you're going to use up some of that energy.

Okay, and that's a normal thing. That's what you should be doing every single day.

And that's why you don't die in your sleep like every single night,

because your body has the ability to pull that energy back out and use it.

But what it means is that you're either in the fed state or you're in the fasted state.

And if you're in the fed state, you're storing fat. If you're in the fasted state, you're burning body fat.

But you can't do both at the same time. So if all of a sudden you are always in the fed state,

you're constantly storing body fat because you've told it to by eating so frequently, okay?

Now, if you wanna hack that, you simply turn the reverse and say, okay, let me spend more time in the fasted state.

And that's a simple, free, easy to do thing. So again, the idea is not new.

It actually goes back to the very origins of medicine. So Hippocrates, who is considered

father of modern medicine, said our food should be our medicine,

our medicine should be our food.

But then to eat when you are sick is to feed your sickness.

And what he means by that is that it's actually instinctive.

So people think that there's something inherently unhealthy about fasting.

But of course, it's part of a natural cycle of life.

And that's why you have the word breakfast.

That's the meal that breaks your fast. So that means you should be fasting every single day.

And what happens when you get sick.

When you get sick, the very first thing you do is stop eating.

So if you have the flu or you get really sick with something,

you don't really want to sit down to a buffet dinner.

You really just can't eat. And the body has naturally told you that you need to activate these hormones,

not store body fat.

You need to activate your body to fight this infection and so on.

So it's actually a very healthy state.

So if you look at the physiology, you hear all kinds of people who say really crazy things like,

oh, you got to eat 130 grams of carbs every day to feed your brain.

If you go more than 24 hours without eating, people don't start having seizures, right?

Like your body needs 130 grams of carbohydrates to function, but it doesn't mean you have to eat it.

You can take it from your body stores because that's what it is.

So if you look at the physiology of what happens to our body during that time, you can see,

and this has been all worked out for many years, that in the first stage, which is the fed state,

it's all exogenous. So the glucose you get is all from your food. As you get into stage two,

what you do is you start to burn glycogen. So the carbohydrates has gone down very low. So

four hours after a meal, you start using your glycogen, which is the stored sugar in the liver.

As you get to 20 hours, 24 hours, what you start is you're tapering off the amount of glycogen

because that's getting used up. And then you start doing gluconeogenesis, which is producing

the glucose from your own protein and also from your fat because your fat, you can take glycerol

and turn it into glucose. So what you're doing is you're really describing a transition from

using carbohydrates or sugar. So as you fast, so this is physiology of fasting, over 30 days of

fasting, what happens is that you stop burning sugar and you start burning body fat. The protein

after this initial little spike goes down. So you're not really burning protein.

And you hear this all the time, oh, you shouldn't fast, you're gonna burn muscle.

It's okay, let's think about that for a second.

You think our body is really just so stupid that we would store body fat as our food energy,

but when we actually need it, we are going to burn muscle, right?

That doesn't make any sense. If that was the case, we would never have survived.

Every time we fasted, we'd lose muscle and gain fat.

We'd really be nothing more than little balls of fat walking around the convention center.

But it doesn't happen. What happens, of course, is that you transition from using sugar to using

fat. And then your body says, whoa, I have tons of this body fat. Let's just use it. No problem.

But there's other very important hormones that go up when insulin goes down. So as you get into

this fasted state, it's not simply a matter of insulin going down. You get this other

counter-regulatory hormone surge, which is the sympathetic nervous system,

adrenaline, growth hormone, and cortisol. All of these hormones go up. So if you're eating all the

time, you're not getting this. So sympathetic nervous system is our fight or flight response.

So when you activate the sympathetic nervous system, you're actually activating the body.

You're taking the glucose and shoving it into the blood so that you can use it to prepare for

action. Same thing with noradrenaline and also growth hormone. And this is why we don't lose

muscle over time when you're doing fasting on a regular basis is because your body actually

activates growth hormone. And when you eat again, your body is going to rebuild all of

those proteins that you need. So what you're doing in essence when you're fasting is actually

something extremely powerful because what you're doing is you're activating the body.

By switching fuel sources. So instead of relying on your food, you're relying on your body

fat, but then you're pumping energy into the system. You're getting more energy.

You're getting, so people say, Oh, you can't concentrate. That's actually the

opposite. People actually concentrate better. They actually think better. They

actually move better. So we work with a number of elite athletes and I always say to them, well...

Think about it for a second. If you just ate a huge meal, do you think you're really sharp? Think

about Thanksgiving when you eat a huge meal. Do you feel really sharp or do you want to just sit

on the couch afterwards? If you are an animal, do you really want to be like that lion who just ate

or do you want to be like the hungry wolf? The hungry wolf is not sluggish lying on the couch,

right? The hungry wolf is activated. And the reason is physiology. The reason is that sympathetic

nervous tone is up, noradrenaline is pumped way up. And then growth hormone, what you're doing is

you're tearing down old proteins in your body and building up new ones. So you're actually.

Renovating your body. You're rejuvenating the body. It's actually a form of anti-aging,

but it's available to all of us for free. If you look at the science of what happens during this,

that as insulin and glucose go down, nor adrenaline, ketones and fatty acids go up,

because that's what you want to burn. So in fact, where do those fatty acids come from?

Comes from your fat. That's the only place it can come from because you're not eating.

So you're putting out fatty acids into the blood so that your liver, your kidneys and so on can

use it. And look at growth hormone. Total control is if you're eating three times a day, it's around

the two and a half jumps up to close to eight,

with a single day of fasting, your growth hormone has gone up like two and a half times

and it continues to go up even up to day five of fast.

So for diseases like osteoporosis and sarcopenia and all these sorts of things,

you actually need that growth hormone and a low growth hormone is going to lead

to weak bones and weak muscles.

And this is the idea that your brain needs the glucose. It actually doesn't because in a normal state

in the fed state, where you can see as your brain is using all glucose, in the

fasted state or starvation, which is longer than a certain period of time,

what you're doing is you're using ketones.

This is all derived from fat.

So in fact, your body has the ability to not.

That's why we carry body fat. It's not there for looks.

It's there because our body needs it when we don't eat.

So we can survive, but not only survive, but if we introduce these regular periods, it's going to be healthier for us.

So the longest the world record for fasting was actually 382 days of fasting.

This guy was monitored in the 70s. He went for more than a year without eating anything.

And he's monitored by his doctors.

What they noted was everything was pretty normal looking at the beginning and at the end.

That's exactly what happens, right? So his glucose went down, but it wasn't too low and it stayed down.

Calcium was normal, his phosphorus was normal, your acid was normal, creatinine, urea, all of that was normal.

All his electrolytes, everybody says, oh, your electrolytes are going to go out of whack.

They don't.

Like this guy went 382 days without eating anything. And we're worried when we go more than three hours without eating anything.

Somebody's going to tell you, oh, your electrolytes are going to go out of whack.

You should eat a muffin.

No, you could go another 300 days if you wanted to. So if we're talking more specifically about weight loss, this is an extremely

powerful hack for everybody to use, because there's actually two problems with weight loss in the longterm.

And it's not calories. Calories is a measure that is not physiologic.

The body doesn't sense calories. It doesn't have calorie receptors.

It doesn't use calories. It doesn't know anything about calories.

What the body responds to is hormones. And the two things that really derail longterm weight loss are

basal metabolic rate and hunger.

So if you look at basal metabolic rate, what happens if you lose weight by cutting a few calories here and there is that your metabolic rate goes down.

So we know this because they take subjects and they force fed them to gain weight and then measure their metabolic rate.

What you find is that when you force them to a 10% weight gain, so they take

these shakes and they tell them, okay, you have to drink this many shakes until you gain weight, after 10% weight gain, they're burning 500 calories per

day more so that their body is actually trying to burn off all that excess those calories you're feeding it.

But when you return them to their initial weight, their metabolic rate goes down.

But then when you lose weight, 10% weight loss, you're burning about 300 to 400 calories per day less.

And that's a real problem. And we always think that if you keep that weight off,

And we know that. It never does. So you can go out to a year,

what you see is that their metabolic rate is down.

If you look at the hunger signaling, that's the other big issue.

So when you cut calories and you lose weight, your hunger goes up.

So you can measure a hormone called ghrelin.

The higher it is, the more hungry you are.

And what you find is that after initial weight loss, the hunger goes up and it stays up even after a year.

So these are the two physiologic responses to weight loss. You're going to lower the amount of calories that you're burning.

And then you're going to get really hungry. And this is not because their weak will.

This is just physiology.

This is what we know happens when you tell people to cut 500 calories a day.

It never works for these two reasons. OK, because if you cut 500 calories a day, then you burn 400 less.

You're not getting anywhere.

Then your body is going to tell you to eat. So it's not a failure of willpower that these people are eating.

They're actually physically more hungry. And if you can't deal with these two issues,

you are not going to be able to keep that weight off because being hungry all the time is no fun.

It's one of our most primal instincts.

So you have to respect that. So how are you going to deal with a lowered basal metabolic rate?

What happens during fasting?

So instead of eating six times a day, what if you eat zero times for four days?

What happens to your metabolic rate?

If you think about the physiology, we know that adrenaline goes up, sympathetic tone goes up.

So your body's gonna burn more energy, not less. That's exactly what we find.

So after four days, this is the weight.

The weight is steadily coming down. This is the resting energy equivalent.

It goes up.

In the VO2, which is a measure of how much metabolism is going on, it goes up.

In fact, after four days, your metabolic rate is actually 10% higher than when you started.

So everybody tells you, oh, if you don't eat, you'll go into starvation mode, your metabolic rate will shut down.

Well, that doesn't happen.

Because if it did, we wouldn't be here. If you think about it, if we're cavemen, for example, and you,

don't eat, then you start to shut down. It's going to be even harder to get food.

So then you're going to not eat and then you're going to shut down your body again. We'd all be dead.

The body's not that stupid. What it does is it simply shifts its fuel sources and then pumps

you full of energy so that you can go out and hunt.

So you actually have more energy at the end of that four days than when you started.

If you look at studies of alternate daily fasting, it's the same thing.

This is the resting metabolic rate. It starts at 6,600 and ends at 6,300,

but it's not statistically significant. So there's not a big change,

even after 22 days of alternate daily fast.

And what you see is that you've gone from burning carbohydrates, burning sugar, to burning fat. That's exactly what you want to do.

So this is the effect on metabolic rate.

So the standard advice, cut a few calories a day, cut 400, 500 calories a day, eat 10 times a day.

What happens is that you will drop, you'll burn 76 calories a day less.

And if you use alternate daily fasting, instead you'll burn 29 less.

So it's a significant difference. So less than 50, 40% of that.

But it's actually not statistically significant.

The P value of 0.41 means that there's actually no statistical difference between the beginning and the end.

And this is after 32 weeks of alternate daily fasting.

And this is a huge advantage.

If you're burning three, four hundred calories a day less, naturally, that's a huge advantage when you're trying to lose weight.

And the other problem is hunger. So, again, everybody says when you're fasting, you're going to get so hungry

that you're not going to be able to control yourself. You'll be forced to stuff a couple of Krispy Kreme donuts in your mouth.

That doesn't happen.

So this is ghrelin. So that's the hunger hormone.

And what is that when you fast somebody for 24 hours, so they get this little spike of ghrelin at breakfast, lunch and dinner.

So you get hungry at breakfast, lunch and dinner. But what happens to you when you don't eat lunch?

Say you're busy, work through lunch. What happens? Do you just get more and more hungry until you stuff a muffin in?

Not really. What happens is that after a while, your ghrelin just goes right back down to baseline.

So, you miss lunch, there's 12 o'clock, you're hungry. At 1 o'clock, you're hungry. At 4 o'clock, it's as if you ate.

You ate. You're no different in terms of hunger if you ate or you didn't eat.

Why? Because again, your body's just not that stupid, right?

If you didn't eat, you will take that energy that you needed from your fat stores.

You've basically made a meal of your own fat. And that's it.

And we've all done this. We've all been busy where we went right through lunch by four o'clock.

Let's go. Did I eat? Did I not eat? Can't remember.

Same thing with dinner. You don't eat. Guess what? It just goes right back down to baseline.

Yeah, you're going to be hungry for a couple hours because it's high here.

And then it's going to go back to baseline. Nothing happens.

Even over multiple days of fasting, which is that up and down.

So you start here, you go up and down.

But what's really interesting is that as you go for two, three,

four days of fasting, ghrelin actually starts to drift downwards.

The hunger actually starts to disappear during fasting.

And that's as your body gets used to using your own body fat.

It just says, hey, why do I need to eat? I'm getting all I need from the body fat.

And that's perfect because now you're dealing with the two actual issues that derail weight loss, which is metabolic grate and hunger.

And people say, oh, women, the women can't do it. Well, this is the breakdown between men and women.

This is durella. So the hunger. See, okay, men get this little spike, but women get this huge spike.

So if you're trying to control hunger, then women are gonna benefit a lot more than men

from intermittent fasting.

If you look at cravings, so the data on cravings is this. If you have cravings for sweets or high fat or junk food or whatever,

versus a very low calorie diet.

So basically very little, like a couple hundred calories a day.

And what you see is that if you measure how much cravings they get,

so a lot of people say, oh, I crave sugar and I'm addicted to chocolate and this kind of stuff.

A low calorie diet, cutting a few calories does nothing for your cravings.

But if you go and just eat nothing at all, your cravings actually disappear.

And it's really just for the parents out there.

If your child has an itch, you don't say, oh, you should scratch it, but a little less.

If no, you don't scratch it. That's what happens to cravings, too.

So over 12 weeks, the cravings, the general cravings or whatever you want to look at

that virtually disappear by the time you follow these low calorie diets or fasting

is the sort of ultimate in that.

But even as you start to eat again, those cravings don't come back for like at least six weeks

and then they start their way up.

So if you were to do this on a regular basis, you could control some of these cravings again,

that derail weight loss efforts because people want to eat bread

and they wanna eat sugar and they wanna eat pizza

and they wanna eat all this sort of stuff.

So again, if you look at Dorelin and all studies, clinical studies, like real people doing this. What you find is that if you look at ghrelin,

which is the hunger hormone, how hungry you are with daily calorie restriction, it goes up with,

calorie restriction, but it doesn't go up with alternate daily fasting. That is, if you cut,

500 calories a day like they told you, you're going to get hungry. If you do the fasting,

you won't get hungry because you've changed the hormone so that in that time that you're not eating,

You're feeding yourself through your body fat.

It's just like a bear, just like during hibernation.

And here's the myth, oh you're gonna burn muscle, oh you're gonna burn muscle. Well, here's the study.

This is real people doing it. Here's the fat mass. Okay, so day 70 of alternate daily fasting,

the fat mass goes down 43 kilos to 38. Fat-free mass, or your lean weight, goes from 51.4 to 51.9.

You actually added lean mass. So for all those people, oh you're gonna burn muscle,

you're gonna burn muscle, you're gaining muscle. This is that study where you're comparing

calorie restriction to alternate daily fasting. You look at two things. One is

the truncal fat mass. So that's the fat that you carry around the waist. It's

much more dangerous from a health standpoint than fat that you carry anywhere else. Calorie restriction goes down by 0.3. Alternate daily fasting

goes down by 1.8. It's six times better at getting rid of the really dangerous

fat for type 2 diabetes. If you look at lean mass, because this is what they say,

oh yeah you're fasting you're gonna lose weight but it's all gonna be muscle. It's no okay so

this is percentage lean mass calorie restriction goes up by 0.5 and alternate daily fasting goes

up by 2.2 percent. In other words preserving lean mass is like four times better with fasting than

to calorie restriction. So the question is why are we doing this? Why do we tell everybody to

to do calorie restriction.

You should never, ever not eat.

It's like, why?

Why don't you let your body just use that body fat? Because that's what's going to make us healthy.

That's what's going to get rid of the type 2 diabetes that's giving us heart attacks, strokes, and cancer.

And it's free, it's available to all of you and used by people like Hippocrates and Benjamin Franklin.

This is the other thing that people say, it's great and everything, but people won't do it.

It's okay, but you know that it's part of almost every major religion in the world.

So literally, the Buddhists do it, the Muslims do it, the Catholics, the Christians, Jewish people.

People, literally billions of people around the world do this on a regular basis and have

been doing this for the last 2-3 thousand years. You know that right? Before you say

that, yeah, nobody can do it. That literally billions of people do it? So yes, you can

do it. It's not fun. I'm not saying it's super fun or anything. But if you're trying to hack

your body to be healthy, to lose weight, to get rid of your type 2 diabetes.

You can do it. It's just a matter of doing it.

Other people say it doesn't work. Yes, we have studies that does work.

And obviously if you don't eat, you are going to lose it.

This is just to show that females get the same rate of weight loss as males.

For all those people that say, oh, women should never fast. It doesn't work.

It's like, where do you think you, what do you think is going to happen?

If you don't, you're going to lose weight.

And then this myth that you need to eat to concentrate. I hear this all the time,

because we've done it in our IDM program for several thousand people,

and people say, oh, I have a really stressful job, or I have to concentrate, I can't fast.

This is what happens when you eat a big meal.

When you don't eat, you actually work from a mental standpoint at a much higher level.

And this is one of the reasons that the people in Silicon Valley in particular have embraced

the fasting so much is because it allows your brain to work at a higher level.

And people who do this say, wow, I can think really clearly.

Yeah, that's because your noradrenaline is up, your sympathetic tone is up,

you're being activated, you're pumping energy into the system,

and your brain is able to think more clearly. And in Silicon Valley, of course,

the difference is that they're competing based on their brainpower, right? So they're all

all these little computer geniuses. They're all trying to get the next best thing. And

that little edge in mental performance can be the difference of millions of dollars.

So they do this because this is what gives them an edge. If you read books,

there is a book called Unbroken by Lauren Hillebrand, which is a story about prisoners

of war, American prisoners of war in Japan in World War II. So these people are literally

starving. And what's interesting is that when you read the biography, they talk about how

their fellow prisoners are doing these absolutely incredible feats of mental capacity. So one

guy is reading books entirely from memory and another one learned Norwegian in a week.

And what he says is that, wow, this is just the astonishing mental clarity of starvation.

I thought, wow, that's really interesting that people who actually do this

have actually noticed that huge improvement

in mental functioning. We see it in our clients all the time.

They say, well, it's like a fog lifted.

I can really focus now on what I'm doing. So if you're looking to hack your way,

into sort of a higher level, fasting is a great way to do that.

So not only just the physical side of things, but the mental side of things.

And that's, again, free. Why won't you do it?

There's another myth here of anorexia that, oh, you're going to cause eating disorders.

First of all, eating disorders are psychological disorders where people think they're fat but they're actually very thin.

And it is a real issue. It's a big issue. People have died from it, of course.

And it's all a matter of context, right? So if you're treating a 16-year-old girl,

with anxiety problems, weighs 80 pounds, then no, you don't want to be fasting.

But if you're 60 years old, male, and have type 2 diabetes, then fasting might just save your life.

So it's a totally different context. You have to use it. It's a very powerful weapon.

But don't use it in the wrong context, right? And that's not what biohacking is about.

It's about getting optimal human performance from a simple lifestyle change.

And then this myth that you cause hypoglycemia. So you're going to go hypoglycemic,

you're going to have a seizure. It's like, that doesn't happen.

Your body is able to deal with it. So here's a study where they took patients

and they actually fasted them for about 30 days.

Then they gave them a big whack of insulin just to see what would happen.

And they drove their sugars down to 227, which is extremely low.

It's 1.2 or something like that.

And for most people, they would actually have seizures at this level.

But they were actually completely fine. All of them were asymptomatic.

That's because your brain is actually working mostly on those ketones.

So if you're using ketones and your blood glucose is low, it doesn't matter because you're using ketones anyway.

So these people actually felt completely normal. And this was the same study.

There are a few concerns. So the Zahn phenomenon is one where your blood sugars can go up slightly during fasting.

And this is very interesting. And it's other than knowing about it, it's not a big concern.

But some people notice, especially type 2 diabetics and so on,

that when they don't eat, their blood glucose goes up and they're always concerned.

And I'm always like, well, it's because of the counter regulatory surge.

So if your blood glucose goes up and you didn't eat, where do you think that sugar came from?

It could only have come from your own body.

Your body is actually liberating that sugar for you to use. So don't worry about it because you're just burning it.

It was in there anyway, but it's actually trying to get it out.

And that's those counter-regulatory hormone surges.

And then the other concern is refeeding syndrome, which again is a real concern if you are not well nourished.

So this is seen in people who are starving and people who have very low body fat.

Those are people who shouldn't be fasting anyway, at least not for extended periods of time.

Just remember that 12 to 14 hours of fasting is a regular amount of fasting.

That's what everybody should be doing because that's the word breakfast.

The meal that breaks your fast. So if you stop eating at 8 and don't eat till 8,

that's 12 hours. But that's normal. That's what should be done every day.

And these people who don't have enough energy, what can happen is that as you eat insulin,

as you start to eat again, the insulin goes up and the phosphorus goes down,

the potassium goes down, it can actually cause heart problems.

But the major risks for that are these issues of people who are basically anorexic, alcoholic,

cancer patients, people who shouldn't be doing this anyway. So again, just remember that this

is a powerful tool and you want to use it in the right context. It's just like a knife, right? A

very useful tool, but you can also cut yourself. So make sure you know what you're doing if you're,

you're gonna apply and make sure you talk to your physician.

But there's so many advantages to using fasting in this way because it's a simple thing.

Everybody can understand it.

So you can have diets like the ketogenic diet is eat this, don't eat this, don't eat this,

don't eat this, sometimes eat this. It's very complicated for people.

This is not that. This is just don't eat for a period of time.

Let your body burn off that body fat.

It's free.

It's convenient because you're going to save a lot of time, right?

You're not, you don't have to buy food. You don't have to cook food.

You don't have to eat food.

But they're going to give you a lot of time back in the day and it's a way to simplify our life.

It's also very flexible in that what you can do is you can do it sometimes and not do it sometimes.

So if you want to, you know, it's the holidays or it's a vacation and you don't want to fast,

then don't. You can always do it later. So that's a huge advantage where you can use it to any diet,

right? Because this is not about your diet. You're trying to hack your way of eating,

but that this doesn't tell you what to eat.

It only specifies the periods of time that you're not eating.

So they work together.

If you fix your eating, cutting out the sugar, cutting out the refined grains,

cutting, trying to eat whole foods, that's great. But fasting doesn't tell you anything about that.

Fasting is complementary to that and tells you there's a period of time where you really just shouldn't eat anything.

So whether it's you don't eat meat or wheat or nuts or you don't have time,

you don't have money, you're traveling, you don't cook, it doesn't matter because you can still fast.

You can still use this sort of biohacking and it gives you unlimited power. That is if you are

400 pounds and we have people who are 400 pounds, you need something really powerful. You can just

keep fasting. You can just keep letting your body use up that fat. You can do it as long as you need

to get healthy and that's the hope.

It's not something that sort of maxes out at, oh, I lost 10 pounds and that's it.

It's great if you only had 10 pounds to lose. If you had 200 pounds to lose, then, you know, you're sort of out of luck.

So it gives you a lot of power. And that's what Mark Twain, another very well-read, a very smart fellow said,

a little starvation can actually do more for the average sick man than the best medicines and the best doctors.

And that's very interesting as we're not talking here about, oh,

Let's get this expensive medication and this expensive procedure because it's

going to make us live an extra three days.

This is something that you do on an ongoing basis to stay healthy for your life.

And if you have type two diabetes, this is Elliot Joslin. So he's the most famous diabetes specialist in the history of the world.

He was at Harvard Medical School. He basically founded the entire floor.

And he said that temporary periods of undernutrition are helpful in the the treatment of diabetes will be acknowledged by all

after these two years of experience with fasting.

That was more than a hundred years ago. The most famous diabetologist in the history of the world

knew a hundred years ago that you could actually just let your body burn off all that sugar

and you won't have type two diabetes anymore.

After two years of doing it, he thought it was so obvious that Everybody's gonna know this.

which will give you heart attacks, which will give you cancer, which will make you blind,

which will give you kidney failure, which will damage your nerves.

So the point is that can we cure type 2 diabetes without all these associated medical problems

and do it without any drugs and without any surgery and really at no cost,

taking really control of the health back into your own hands? And the answer is yes. That's all you

need to do is understand the physiology, understand what we're trying to do. And now you have the

power to get rid of type 2 diabetes, to lose weight, take care of all these metabolic problems

that are now making us sick. And that really is the ultimate in biohacking. Thank you.

(Teemu Arina speaking) Thank you very much Dr. Jason Fung for such an in-depth introduction to the benefits of

therapeutic fasting. Here are the top five scientific facts of the day about therapeutic

fasting that have been backed by science.

Number one.

Fasting and intermittent fasting have been shown to improve insulin sensitivity,

reduce blood sugar levels and protect against type 2 diabetes.

Number two. Intermittent fasting has been shown to be effective tool for weight loss

and improving metabolic health.

Number three. Fasting triggers the process called autophagy,

which is the body's natural mechanism for cleaning out damaged cells and recycling their components.

This may help reduce the risk of chronic diseases and slow down the aging process.

Number four. Fasting and intermittent fasting may improve brain function and protect against

neurodegenerative diseases like Alzheimer's disease or Parkinson's disease.

Number five. Fasting and intermittent fasting have been shown to reduce inflammation in the body,

which is a key driver for many chronic diseases.

Next I will give you some tips on doing intermittent fasting in an effective way.

I do not recommend to go to a multiple day fast straight away as most benefits are achieved already with intermittent fasting.

But either case I will give you a short summary of what you would expect at certain hours,

while you are going into a fast.

In a 20 hour fast also known as intermittent fasting one already improves insulin sensitivity and activates autophagy

which is the body's natural process for cleaning out damaged cells.

In a 24-hour fast one can improve heart health by lowering blood pressure and improving cholesterol levels.

In a 48-hour fast you're already regenerating part of the immune system,

you will promote further fat burning and you will get increased improvements in insulin sensitivity.

In a 72-hour fast you start to boost stem cell production, which can potentially help regenerate damaged tissues and organs.

It may also improve cognitive function and enhance mental clarity.

Fasting more than 72 hours on a regular basis doesn't really provide much additional benefits

and can actually lead to electrolyte imbalances, malnutrition,

gallstone formation and potentially also loss of muscle mass.

My recommendation is to first learn how to do intermittent fasting properly on a regular basis.

It already provides you a lot of metabolic and cognitive benefits,

so let's get started with that one. Personally, I highly recommend trying out the popular OMAD

or one meal a day method that involves fasting for 20 hours a day and eating all calories during a four-hour window.

That effectively means that you skip breakfast and lunch and then consume all meals of the day within a four-hour window.

When you wake up you are already in a fasted state, so it's easier to continue from there as you are effectively burning ketone bodies already.

Start by doing this once a week and then slowly increase to doing it every second day.

Eventually you notice yourself doing it every single day.

An advanced version of this is called time-restricted eating,

where you actually time the consumption of calories before sunset.

That has shown to be additionally beneficial for metabolic health and circadian rhythm timing.

If this all sounds too hard, feel free to drink a cup of coffee or tea with butter or MCT oil in

morning and then skip breakfast and lunch. MCT oil helps to kick start the process of fasting,

because it produces ketone bodies as a by-product. In either case it is important to stay hydrated

during the day and I recommend you to add electrolytes into your water. If you have

a medical condition first consult your health care professional. Thank you very much for listening.

To learn more about us and biking check out biohackercenter.com where you can find best content, supplements, technologies,

courses, retreats and events such as the Biohacker Summit so that you can take your

health and habits to the next level. That's all folks - see you in the next one.