Does fat physically leave your body when you lose weight? (see details!)

Fat is fuel. It burns off.

I think the missing detail here is fat molecules vs. fat cells.

How Fat Cells Work, everything you ever wanted to know about fat.

The fat leaves the body and the cells remain as empty cells, but they’re easier to refill than building new cells, so it’s easier to regain the weight.

Yes, research has shown that the fat cells taken away by force can return within several years according to your numbers threshold made in adolescence. The amount of fat in the cells is controlled by diet (amount and types of foods) and exercize.

Fat cells stay. The fat stored in them is (hopefully) burned up.
You are genetically determined to have a certain number of fat cells, in certain places.
What you do about calorie/metabolism management determines how much fat they actually store.
Liposuction removes fat and cells.
Your body begins replacing the cells. If you are not managing calories/metabolism, the new fat cells load up again.

@syz – Thank you for that link! Very interesting.

@all – Thank you for the helpful and informative answers!

No, it is metabolized.

No, your fat cells just shrink.

I remember reading that we add fat cells when we are young. And, that once we are adults we have a set number and they either shrink or expand. Supposedly, the fat cells you have want to stay full, so being a heavy child can screw you for the future. But, I think that was a theory maybe? Possibly not proven.

Anyway, as adults I agree with the people above, you gain and lose fat, but the fat cells are still there.