Credit: Juliette Borda

Juliette BordaQ: I just lost a lot of weight. Where did it go?

A: It may look like your body is literally disappearing, but whats really happening is this: When you eat fewer calories than you need to power your daily activities, your body begins burning stored fat. You dont actually lose fat cells—the cells merely shrink as the fat inside them is broken down to generate energy. The end products of this process are water, which you lose in the forms of sweat and urine, and carbon dioxide, which you breathe out. Good-bye, extra pounds!