Dr. Jason Fung

If it gets too hot, the thermostat will sense it.

It'll turn on the air conditioning.

If it gets too cold, it's going to turn on the heat.

So that's homeostasis.

And that's the only way we survive.

So every single sort of mission critical system in the body follows homeostasis.

So if you think about body temperature, the same, right?

So if you are hot, you're going to sweat to cool down.

If you're cold, you're going to shiver to warm up.

If your sodium is very high, then you're going to pee it out.

If you drink a lot of water, you're going to pee it out.

If you don't drink a lot of water, you're not going to pee it out, right?

Your electrolytes are the same.

Your body water is the same.

You know, if you go into a bright room, your pupils, you know, shrink, constrict.

If you go into a very dark room, you know, they'll dilate to, again, keep that homeostasis.

And body fat is the same.

How much body fat you carry is actually crucially important for survival.

If you think about basically all animals, they have to maintain a relatively stable body fat.

Why?