Do Not Limit Calories Before Competition

Most athletes know that lack of fluids weakens and tires them, so they take adequate amount of fluids, before, during and after competitions. However, many do not know how much they need extra calories. They often are told incorrectly that the human body as so much fat on board that lack of calories is not a significant problem. Researchers at the University of Wales in the United Kingdom found that moderate calorie restriction two days prior to competition slows down endurance far more than reduced fluid intake over that same period (Medicine and Science in Sports and Exercise, February 2007). Moderate dehydration does not harm performance until a person becomes severely dehydrated. On the other hand, lack of calories stops you cold in your tracks.

Dehydration does not limit endurance until a person loses enough fluid to decrease blood volume, which takes a long time. However, endurance during exercise depends on having enough sugar stored in your muscles. When you exercise, you get energy from fat and sugar stored in muscles, fat and sugar from the bloodstream, and to a lesser extent, from protein. When your muscles run out of their stored sugar, they can hurt and you will find it more difficult to coordinate them. This happens no matter how much energy you have stored in body fat, which is virtually limitless during almost all athletic events. So a major nutritional principle of endurance exercise is to store as much sugar in muscles as possible and preserve that sugar supply for as long as possible. When you reduce calorie intake, you reduce your stored muscle sugar supply, so you should never fast or reduce calorie intake prior to athletic competition. In a few sports, athletes must lose weight so they can compete in a lower weight class, but they can compensate to some extent by eating as much as possible just before they start their competition. More