There has been some evidence that working out on an empty stomach help in weight loss. But come to find out, it isn't as simple as that. Proponents of exercising while “fasted,” or in a state of hunger, suggest you can speed up your weight loss by doing so. Backing this claim is a study in which participants who exercised while fasted burned nearly 20% more fat than those who ate before beforehand. And another study had similar findings, suggesting aerobic training in a fasted state lowers more body fat percentage in addition to body weight when compared to fed training. But here is what happens. To perform intense physical actions like running or lifting weights, your body has to burn glycogen, or your stored up carbohydrates. Once your body runs out of glycogen reserves, like it would in a hungry/fasted state, it switches to burning fat to keep you going. But when you burn fat rapidly, your body begins to adjust your metabolism to compensate for that loss. Basically, it goes into a kind of survival mode and starts to burn fewer calories. By burning so much fat, your body thinks it needs to store more of it when you eat your next meal, completely counteracting those fat-burning benefits. So there’s no real upsides to foregoing food in this type of scenario. Fasted exercise can cause you to shed some muscle in addition to fat under some circumstances. If your body has burned through its glycogen fuel stores, it may also obtain energy by breaking down muscle proteins in addition to those fats. Intense training always breaks down muscle so it can get stronger through protein synthesis, but doing so while fasted harvests more muscle sooner, making it more difficult to recuperate the lost mass. Whether you work out hungry or not, you can do your usual thing at the usual intensity without worrying about muscle loss because you generally do not run out of carbs for energy. It’s feasible to work out on an empty stomach and get by just fine. Some people prefer it because they feel lighter, are more alert, and experience increased focus. But beyond personal preference, there’s not many benefits.