Some scientists say that athletes who want to burn fat should avoid eating before exercising. Some athletes eat before training, several studies indicate that exercise when the body contains little food could be a good way to eliminate fat. In a recent paper, European researchers found that cyclists who trained before eating burned a much larger amount of fat than those fed first.
Muscles tend to take energy from carbohydrates. This is the reason why top athletes can eat much before a competition. However, if the athlete has not eaten, your body does not have many carbohydrates in their reserves, thus forcing your system to burn fat, scientists say.
“When you exercise (without eating), adrenaline and insulin is high, low,” said Peter Hespel, a professor of exercise physiology at the University of Leuven in Belgium. “That relationship is good for muscles to oxidize (dissolve) more fatty acids.” That is why those who train without having eaten burn more fat than if they had, he said.