Quick questions on Diet and nutrition for performance: WACE Physical Education Studies Unit 3

Carbohydrate is the body's main fuel for moderate to high intensity exercise. It is stored as glycogen in the muscles and liver and converted to glucose for energy. Because glycogen stores are limited, they can be depleted in prolonged or repeated high intensity exercise, which causes fatigue. A diet high in carbohydrate keeps glycogen stores full, supporting both training and competition.

Fat is a large energy store and the major fuel for low intensity, long duration activity, where there is enough time and oxygen to break it down. It supplies energy more slowly than carbohydrate, so it cannot fuel high intensity work alone. Trained endurance athletes become better at using fat, which spares glycogen and delays fatigue.

Protein's main role is to build and repair muscle tissue, including the repair and growth that follow training. It is not a major energy source under normal conditions, contributing significantly only in extreme endurance or when carbohydrate is exhausted. Adequate protein supports the adaptations of resistance and endurance training.

Before endurance events, athletes may carbohydrate load, increasing carbohydrate intake in the days beforehand to maximise glycogen stores so they last longer into the event. A pre-event meal rich in carbohydrate, eaten with enough time to digest, tops up the stores.