Mobilized fatty acids must be oxidized within mitochondria to be converted into ATP; otherwise, they can be re-stored as body fat.

“They're going to go into cells that can use them for energy. And once they are inside those cells, they're still not burned up. You need to oxidize them. Think oxidation is the burnup part. They need to be moved into the mitochondria and then they can be converted into ATP into energy. ... If you just mobilize it, and you don't convert it into energy, you don't oxidize it, it can be returned to body fat.”