Exercise burns more calories before you eat

So the theory goes. However, according to researchers, there is no simple rule. A 1995 study found that a group of people did burn more calories from fat on days when they exercised on an empty stomach than on days when they had a small breakfast first. But the researchers found that the difference was negligible, and other studies have shown fewer calories are burnt in the long run because the workouts are shorter.

If you exercise on an empty stomach, your body may compensate by burning less fat after you finish exercising and eat a meal. This effectively balances out the overall levels of fat you use as fuel.