A recent study found that cyclists who exercised without eating beforehand burned considerably more fat than cyclists who ate prior to training.
Researchers at the University of Birmingham and elsewhere monitored outcomes for 14 study subjects who cycled three days a week. One group of seven was instructed to fast after their training and then exercise again an hour later. The other seven participants followed the same regimen but were told to eat before the second training session.
The participants who fasted performed worse on their training, but they also burned more fat than carbohydrates when compared to the group that ate before cycling.
Scientists note that muscles mostly get energy from carbohydrates, which is why top athletes like Lance Armstrong and Michael Phelps consume copious amounts of food before big races. But if you haven’t eaten before exercising, your body does not have as many carbohydrates to feed off of, forcing you to burn fat instead of carbs.
Other experts argue that although people tend to burn more fat by fasting before a workout, they will not see a big difference if they are attempting to lose weight.
“You may enhance how you burn the fat in the muscles, but it doesn’t affect your overall body fat,” Dr. Andrew Greenberg, director of the Obesity and Metabolism Laboratory at Tufts University, told the Associated Press (AP).
Dr. Alexis Chiang Colvin, a sports medicine expert at Mount Sinai Hospital in New York, recommends eating before exercise to prevent dizziness due to low blood pressure, which could lead to an injury. Having a small snack, like a banana, before training is important because the body needs to have enough nutrients to recover from a workout, she told the AP.
Results of the study were published by Medicine & Science in Sports & Exercise, the journal of the American College of Sports Medicine.
