Carbohydrates are used by the body for energy and for high-intensity exercises; they are our body’s premium fuel; although our body also uses fats for fuel, they do not burn as efficiently. The body’s most efficient energy source is carbohydrates, which is why a diet that calls for restricted carbohydrate intake ultimately lowers an individual’s energy and performance levels.

The body stores carbohydrates as the main energy source and fat as a backup energy reserve. For low intensity, long duration exercises, an individual’s energy is derived from fat while for high intensity exercises, glycogen (carbohydrate) is used as the main fuel.

Since carbohydrates are the more efficient fuel source compared to fat, they are the limiting factor in athletic performance. Strenuous physical activity quickly uses up muscle glycogen for fuel and if you fail to replace it by eating high carbohydrate foods daily, the body’s glycogen stores quickly diminishes. In doing weight training and high intensity exercises, glycogen is the primary energy source of the body. This explains why your energy levels are low when you don’t eat enough carbohydrates.