Dr. Jason Fung

There's cortisol is a very important hormone.

Yeah, and it's probably a very, very small effect for a couple of reasons.

So we know that if you exercise, and I say this, exercise is really good for you in a number of ways.

Flexibility, strength, core, all kinds of things.

So very, very important.

But in terms of weight loss, it's actually a very, very small effect.

Why?

Because one, the amount of calories you burn during exercise are simply not that high.

So if you look at, you know, if you do walking, I mean, if you did eight hours of high intensity exercise, yeah, you're going to burn a lot of calories.

But most people I deal with, which are sort of middle-aged and higher, you're talking about sort of a quick walk or, you know, 45, half an hour, three times a week sort of thing.

And if you ever go on the treadmill and you ever watch the calorie counter on the treadmill, you know it goes up very, very slowly, right?

You'll do half an hour and it'll be up to like 120 calories or something like that, right?

So that exercise really didn't burn off very many calories.

It's the amount that you'd get in a couple of cookies, for example, right?

So it's just...

numerically it's just very small.

So if your body is normally using 2000 calories with your brain generating body heat, your heart, your lungs, your liver, they're using 2000 calories and now you go up to 2100 calories.

Well, percentage wise, it's not a huge deal, right?

The other problem with exercise is that it tends to actually cause you to eat more.

So again, we've had decades of study for this.