Should you feed or starve your muscles during workouts? Written
by: Matt Fitzgerald We all know that consuming carbohydrates
during strenuous endurance exercise enhances performance. Given
this fact, it would seem to be a good idea to consume carbs, in
a sports drink or gels, during every long or hard run, as the
resulting elevated performance in each workout would yield a
stronger training effect that, over time, would add up to
greater fitness. However, recent science has shown that the
opposite is true. The body actually depends on the depletion of
carbohydrate (that is, glycogen) stores in the muscles and liver
to trigger some of the positive physiological adaptations to
training, such as increased fat-burning capacity. When carbs are
consumed during a workout, the body’s own carbohydrate stores
become less depleted and there is a less pronounced training
effect. Even so, research has shown that while training in a
glycogen-depleted state enhances low-intensity endurance in
mice, it does not enhance high-