Explain the role of carbohydrates, fats, proteins and fluids in fuelling performance and recovery, including pre-event, during-event and post-event strategies.

What this dot point is asking

You must explain the roles of the major nutrients and fluids, and describe nutrition and hydration strategies before, during and after activity.

The fuel nutrients

• Carbohydrates are stored as glycogen in muscle and liver and are the dominant fuel for moderate to high intensity exercise. Glycogen stores are limited, so depletion is a major cause of endurance fatigue.
• Fats are an almost unlimited energy store and the main fuel at low intensities and rest, but they release energy slowly and need oxygen, so they cannot fuel high intensity work.
• Proteins are mainly for growth and repair of muscle tissue rather than fuel, contributing energy only when other stores run low.

Hydration

Water regulates body temperature through sweating and maintains blood volume. Even mild dehydration (around 2 percent of body mass lost) raises heart rate, increases perceived effort and impairs performance and concentration. In long or hot events, electrolytes such as sodium are also lost in sweat and must be replaced.

Nutrition and hydration strategies

Before the event.

• Eat a carbohydrate-rich meal a few hours before to top up glycogen.
• Endurance athletes may carbohydrate-load in the days before a long event to maximise glycogen stores.
• Hydrate well in the hours beforehand.

During the event.

• For events over about 60 to 90 minutes, take in carbohydrate (sports drinks, gels) to spare glycogen and maintain blood glucose.
• Drink fluids regularly to limit dehydration, with electrolytes for long or hot events.

After the event.

• Replace carbohydrate promptly to restore glycogen, which is slow and takes 24 to 48 hours.
• Include protein to support muscle repair.
• Rehydrate by replacing more than the fluid lost, with electrolytes to retain it.

Linking nutrition to recovery and training

Nutrition is part of the recovery principle. Without adequate carbohydrate, glycogen does not restore between sessions and performance declines; without protein and rest, muscle does not repair and adapt. Good nutrition therefore enables the adaptations that training stimulates.

Because the optimal fuel mix depends on the intensity and duration of the event, nutrition strategy must be matched to the demands of the sport. A power athlete competing in short bursts relies less on glycogen sparing than a marathoner, who must defend limited stores across hours, while a team-sport athlete with intermittent high-intensity efforts needs carbohydrate availability and rehydration across a long match. The strongest answers do not just list nutrients but justify a timed plan for a specific athlete, explaining which fuel each strategy protects and how it links to the energy systems and the recovery the next session depends on.