That is, unless you're making a passing remark about your friend with a fast metabolism who can eat anything and everything.

Is there such a thing as a fast or slow metabolism?

With her tiny size and fast metabolism, every meal was processed quickly, and she couldn't wait too long for the next.

She has super speed (running 10 miles in just under five seconds) and an incredibly fast metabolism that allows her to heal quickly.

They also have very fast metabolisms and must feed almost continuously.

She is noted for her extremely fast metabolism.

Has a fast metabolism and requires a lot of food.

It is characterized by very rapid movements and a fast metabolism, eating about 1.5-2 times its own body weight per day.

"Christ, I hate people with fast metabolisms," she said.

"And the life-forms would have less oxygen to drive fast metabolisms like ours."