Sports and Nutrition
Domain focus
Sports nutrition tests the balanced diet, macro- and micronutrients, timing of meals, hydration and the evidence around supplements. PSEB favours applied questions about the athlete's plate and competition day.
Core concepts
- Macronutrients: carbohydrates 55–65% of energy for most athletes; fats 20–30%; protein 1.2–2.0 g/kg/day depending on sport.
- Micronutrients: vitamins and minerals; iron for oxygen transport, calcium for bone, vitamin D for calcium absorption.
- Balanced diet: energy and nutrients in the right proportion, with fruit, vegetables, whole grains, pulses, dairy or alternatives, and lean protein.
- Timing: a carbohydrate-rich meal 3–4 hours before competition; a small carbohydrate snack 1–2 hours before; carbohydrate and protein within 30–60 minutes after.
- Hydration: drink before, during and after; urine should be pale yellow.
- Deficiency: vitamin A - night blindness; B1 - beriberi; C - scurvy; D - rickets; iron - anaemia.
Worked example
A 60 kg endurance athlete needs 6–10 g carbohydrate/kg/day. That is 360–600 g/day. If the athlete eats 300 g, the diet is short by 60–300 g. Reasoning: multiply body mass by the g/kg range; do not give a single number. Add protein at 1.2–1.6 g/kg = 72–96 g/day.
Traps
- Saying protein is the main energy source.
- Recommending a heavy fat meal immediately before competition.
- Treating all supplements as safe; contamination is a doping risk.
- Ignoring fluid loss in hot weather.