Whether you exercise before or after eating, the amount of fat floating in your blood doesn’t change much during the workout — so the extra fat burning when fasting must be happening inside the muscles, not from more fat being released.

Even though your body burns more fat when you exercise before eating, the amount of fat in your blood doesn’t go up — so the extra fat burning must be happening inside your muscles, not because more fat is being released from fat cells.

Working out before eating breakfast burns about 3 grams more fat than working out after eating, because your body has to use stored fat for energy when you haven’t eaten.

Whether you're fit or out of shape, male or female, young or older, working out before breakfast still burns more fat than after eating — as long as you're not sprinting at max effort.

When you work out in the evening without eating beforehand, your body burns more fat and less sugar for energy during the workout.