Diet, energy and performance
Physical Education · GCSE · The School
The groups
CARBOHYDRATE is the main energy source for exercise. PROTEIN builds and repairs tissue. FAT is a concentrated energy store and carries some vitamins. VITAMINS and MINERALS enable body processes — iron for oxygen transport, calcium for bone. FIBRE aids digestion. WATER is required for nearly everything.
Hydration
Even 2% dehydration measurably reduces performance and concentration before you feel notably thirsty — thirst is a late signal, not an early one. In endurance events, losing salts matters as well as losing water, which is what electrolyte drinks address. Drinking far too much plain water is also dangerous, which is a genuinely counter-intuitive point.
Diet and the sport
An endurance athlete emphasises carbohydrate to fuel long efforts. A strength athlete emphasises protein for repair and growth. Timing matters too: carbohydrate before, protein and carbohydrate after. Answering 'eat healthily' earns nothing; naming the nutrient, the reason and the sport earns the marks.
A MARATHON RUNNER the night before a race: high carbohydrate — pasta, rice, bread — to fill glycogen stores, moderate protein, low fat and fibre so digestion is easy. A SPRINTER or weightlifter in training: adequate carbohydrate for the session, and protein spread across the day for repair and adaptation. Same nutrient groups, very different proportions, because the events demand energy over different timescales.