I have trouble exercising on an empty stomach, but a study in The Journal of Physiology suggests we should try to do so. In the study, as covered in the New York Times, a pool of men, who were all stuffed with “a truly lousy diet” were divided into three groups:
- those who did not exercise,
- those who exercised before breakfast, and
- those who exercised after breakfast.
After six weeks, it was the before breakfast group that had fared the best.
“Only the group that exercised before breakfast gained almost no weight and showed no signs of insulin resistance. They also burned the fat they were taking in more efficiently. ‘Our current data,’ the study’s authors wrote, ‘indicate that exercise training in the fasted state is more effective than exercise in the carbohydrate-fed state to stimulate glucose tolerance despite a hypercaloric high-fat diet.'”
One possible explanation of this phenomenon is the fact that in a fasted state the body burns a greater percentage of fat for fuel, as opposed to the carbs that would be used right after a meal. Every bit of fat that gets burned is fat that’s not getting stored in your muscles.
Unless you’re an athlete who’s seeking to maximize performance, in which case fueling your body with a high-carb diet is probably beneficial, try to set that alarm clock and squeeze a workout in before breakfast next time.