It’s kind of a perpetual question among gym rats: Is it better to eat before working out, or lift fasted? They both have their pros—getting in some carbs and protein before hitting the gym can give you some extra energy to get through tough lifts or intense HIIT sessions, but going in sans food makes some people feel lighter and more active, ready to attack the workout.
A recent study from the University of Bath in the U.K., which was published in the American Journal of Physiology – Endocrinology and Metabolism, investigated this popular query by gathering a small group of overweight guys with the average age of 26 and average waist size of 41". The researchers then put them through a moderate treadmill test of an hour either on an empty stomach or two hours after eating a high-carb breakfast, and took blood samples after eating or fasting and after the workout.
The researchers found that the fat in the men responded differently whether they were in the fasted or fed state before exercising. By checking the gene expression of the tissue, they saw that two genes linked to burning stored fat and energy were activated when the fasted men worked out, but those genes had decreased expression when the guys who ate breakfast hit the treadmill.
The study, say the authors, strengthens the idea that fat tissue is often asked to perform conflicting tasks. Co-author Dylan Thompson, Ph.D., says in the study that when you are done eating, adipose tissue “is busy responding to the meal and a bout of exercise at this time will not stimulate the same [beneficial] changes in adipose tissue. This means that exercise in a fasted state might provoke more favorable changes in adipose tissue, and this could be beneficial for health in the longterm.”
We recommend just going with your gut in this case unless you are trying to seriously lose weight. Some people just don’t like working out after eating, even if it is an hour or so after. Other guys just can’t imagine getting under some iron without some fuel ready to provide energy. Check out these great pre-workout foods for a quick and easy way to fuel up before your next gym visit.