If the activity continues long enough, even the body's fat cells get in the game.

This type of scrape looks white at first, and fat cells may be visible.

The other type, without Myf5, may share the same origin as white fat cells.

Individuals who become obese as adults have no more fat cell than they had before.

Individual fat cells can balloon up to 10 times or more their original size.

So where does the material to make these fat cells come from?

High levels of calcitriol "tell" fat cells to store themselves in the body, he says.

It is not uncommon to also have mature fat cells.

I always told you one day these fat cells would come in handy.

"The liver is sensitive to things that fat cells put out," he said.