Nutrition, Balanced Diet, Diet Planning and Eating Disorders
Nutrition questions move from definitions to arithmetic: what a balanced diet is, how to plan one, and how to recognise an eating disorder.
Nutrients
- Macronutrients - carbohydrates (main energy source, 55–60% of intake, prefer complex), proteins (growth and repair, 10–15%), fats (concentrated energy, 20–30%, prefer unsaturated).
- Micronutrients - vitamins and minerals; plus water and dietary fibre.
Balanced diet
A diet supplying all nutrients in the proportions and quantities required for energy, growth, repair and regulation - varied, adequate, moderate and hygienic. BMR (basal metabolic rate) is the energy needed at complete rest, and it sets the base figure a diet plan is built on.
Diet planning steps
- Estimate energy need from age, sex, body weight and activity level.
- Fix the macronutrient split.
- Choose foods by food groups (cereals, pulses, milk, fruits and vegetables, fats).
- Spread intake over 4–6 meals, with pre- and post-training meals timed.
- Ensure hydration, iron, calcium and micronutrient density.
Eating disorders
- Anorexia nervosa - severe restriction, intense fear of weight gain, distorted body image, low BMI, amenorrhea.
- Bulimia nervosa - recurrent binge eating followed by purging (vomiting, laxatives, excessive exercise); weight often near normal.
- Binge-eating disorder - binges without purging, often with obesity.
- Obesity - excess body fat from energy imbalance; a risk factor for diabetes and hypertension, not an eating disorder as such.
Worked example
A 60 kg athlete needs roughly 1.2–1.6 g protein per kg, i.e. 72–96 g daily. Split as 25 g at breakfast, 30 g post-training and 30 g at dinner. Show the multiplication and the meal timing; both carry marks.
Traps
- Calling fat unnecessary - it is essential for fat-soluble vitamins.
- Confusing anorexia with bulimia: anorexia shows low body weight, bulimia usually normal weight.
- Forgetting water and fibre in a balanced diet answer.