Most Endurance athletes are concerned about their weight and periodically diet. Since each pound contains about 3,500 calories, if we reduce caloric intake by 1,000 calories each day we lose about two pounds each week. Logically, the higher the daily caloric deficit, the faster the weight loss. Unfortunately, the faster that you drop the weight, the more muscle you lose.
This observation was made by researchers at Rockefeller University. The researchers looked at the effect of daily caloric deficit on weight loss. As might be expected, the less calories consumed the more weight was lost. What wasn’t expected was where the weight loss was coming from. For individuals who moderately reduced their daily caloric intake, 91% of the loss was fat and 9% was muscle. For subjects who severely reduce their daily caloric intake, fat represented 48% of the loss and muscle 42%. In other words, the greater the daily calorie restriction, the greater the loss of muscle mass. For endurance athletes, the implications are pretty obvious.
This research also explained why the longer one is on a diet that severely restricts calories, the harder it is to keep losing weight. As the body loses more muscle mass, it has a dramatic effect on overall energy metabolism since a resting muscle cell burns almost eight times more energy per day than a fat cell.
Ironically, severe calorie restrictions are unnecessary. A recent study showed that a group who had a 200 calorie per day deficit has the same weight loss at six months as a group that had a 750 calorie per day deficit. The bottom line – if you want to lose fat, not muscle, a moderate diet plan is the only way to go.