Mealtime and body composition influence weight loss results
If you're exercising to burn calories and lose weight, you may want to consider what time you exercise in relation to when you eat.
A study from Mount Sinai Hospital in New York showed that obese men (30 percent of their body weight was fat) burned more calories if they exercised immediately prior to eating. On the other hand, lean men (their body weight averaged 13 percent fat) burned more calories when they did the opposite, and ate right before exercising.
You would think that everybody would burn more calories if they ate first and then exercised. Obesity, however, causes the cells in your body to be less sensitive to insulin (the hormone that converts food stored in the body to energy). Exercise increases your cells’ "sensitivity" to insulin and allows it to work more efficiently. This is the reason diabetics can often lower their need for insulin with regular exercise.
Regular exercise does more than just burn calories; it can also raise your resting metabolic rate (RMR). In other words, exercising can help you burn more calories throughout the day. One study showed that exercise could increase the RMR by 12 percent. This means you could burn as much as 100 to 250 calories throughout the rest of the day after exercising.