Nutrition, Balanced Diet and Healthy Lifestyle
This domain covers nutrients, the balanced diet, deficiency diseases and eating for sport and everyday health.
Macro and micro nutrients
- Carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g. Water and fibre supply no energy but are essential.
- Fat-soluble vitamins: A, D, E, K. Water-soluble: B-complex and C.
- Minerals: iron for haemoglobin, calcium for bone, iodine for thyroid function.
Food groups in a balanced diet
Energy-giving (cereals, roots, oils), body-building (pulses, milk, egg, fish, meat) and protective (fruits, vegetables). A balanced diet supplies all nutrients in the proportions the body needs, with fibre and adequate water.
Worked example
A day's intake is 250 g carbohydrate, 60 g protein and 50 g fat. Energy = (250 × 4) + (60 × 4) + (50 × 9) = 1000 + 240 + 450 = 1690 kcal. Reasoning: apply the 4–4–9 factors per gram in that order, then add. If the athlete's requirement is about 2200 kcal, the plan is short by roughly 510 kcal, and the sensible correction is extra carbohydrate around training rather than extra fat.
Traps
- Using 9 kcal/g for protein.
- Confusing deficiency diseases: night blindness (A), rickets (D), scurvy (C), beriberi (B1), anaemia (iron), goitre (iodine).
- Assuming more protein automatically builds more muscle.
- Eating a large meal minutes before competition; a normal meal needs about three to four hours.
- Ignoring water - a loss of about 2% of body mass already reduces performance.