During digestion, all carbohydrates are broken down into sugar (glucose), which is the body’s primary energy source. Glucose can be converted into glycogen and stored in the liver and muscle tissue. It can then be used as a key energy source during exercise to fuel exercising muscle tissue and other body systems. Athletes can increase their stores of glycogen by regularly eating high-carbohydrate foods.
If carbohydrate in the diet is restricted, a person’s ability to exercise is compromised because there is not enough glycogen kept in storage to fuel the body. This can result in a loss of protein (muscle) tissue, because the body will start to break down muscle tissue to meet its energy needs, and may increase the risk of infections and illness.
Carbohydrates are essential for fuel and recovery
Current recommendations for carbohydrate requirements vary depending on the duration, frequency and intensity of exercise. Foods rich in unrefined carbohydrates, like wholegrain breads and cereals, should form the basis of the athlete’s diet.
Athletes are advised to adjust the amount of carbohydrate they consume for fuelling and recovery to suit their exercise level. For example:
Light intensity exercise (30 mins/day): 3–5 g/kg/day
Moderate intensity exercise (60 mins/day): 5–7 g/kg/day
Endurance exercise (1–3 hrs/day): 6–10 g/kg/day
Extreme endurance exercise (more than 4 hrs/day): 8–12 g/kg/day