Food, Nutrition and Health
Core concepts
A candidate must know the six nutrient classes (carbohydrates, proteins, fats, vitamins, minerals, water), their energy values (carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g), and their main functions. Understand macronutrients versus micronutrients, complete versus incomplete proteins, soluble versus insoluble fibre, and fat-soluble (A, D, E, K) versus water-soluble vitamins. Know the diet-related conditions: obesity, undernutrition, anaemia (iron), rickets (vitamin D), scurvy (vitamin C), and dental caries. Be able to apply dietary guidelines and the concept of a balanced diet across life stages - infancy, adolescence, pregnancy, and old age.
Traps to watch
- Energy values are often swapped in distractors; fat is always the highest at 9 kcal/g.
- Water-soluble vitamins are not stored in the body in significant amounts, so excess is excreted; fat-soluble vitamins can accumulate to toxic levels.
- Fibre provides no energy to humans but is essential for bowel health.
- Confusing deficiency with excess: iron deficiency causes anaemia, but iron excess is also harmful.
Worked example
A meal contains 60 g carbohydrate, 20 g protein, and 10 g fat. Energy = (60×4) + (20×4) + (10×9) = 240 + 80 + 90 = 410 kcal. Show each step; questions often ask for the contribution of one nutrient as a percentage: fat here is 90/410 ≈ 22%.
Rule of thumb
Match the nutrient to its function and its deficiency disease; that pairing answers most exam items.