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.

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.

Doing a tough weight workout before jogging or cycling helps your body burn more fat while you're doing the cardio.

When endurance athletes do high-intensity interval training at very hard effort (over 85% of their maximum oxygen capacity), they burn fat at extremely high rates - about 1.58 grams per minute on average, with some burning over 1.85 grams per minute. These are the highest fat-burning rates ever measured in people.

Even if you exercise, your body won't burn more fat over the day if you eat back the calories you burned — it's more about whether you're in a calorie surplus, deficit, or balance than the workout itself.

If a fit guy burns more carbs during a tough workout, he's likely to burn more fat afterward while recovering.