Food, Nutrition and Health
This domain tests whether you can move from nutrient science to real diets: the functions of nutrients, the Dietary Reference Values (DRVs) used in the UK/Maltese tradition, dietary analysis, and the diet–disease links that underpin public health advice.
Energy and the DRV framework
- Atwater factors: carbohydrate 17 kJ/g (4 kcal), protein 17 kJ/g (4 kcal), fat 37 kJ/g (9 kcal), alcohol 29 kJ/g (7 kcal).
- Learn the four DRV terms precisely: EAR meets the needs of half the population group; RNI covers 97.5%; LRNI covers only 2.5% (intakes below it are almost certainly inadequate); safe intake is used where data are insufficient.
Benchmarks to quote with confidence
- Protein RNI for adults: 0.75 g per kg body weight per day.
- Fat no more than 35% of food energy, saturates no more than 10%, free sugars no more than 10% (ideally 5%), fibre 30 g/day (AOAC), salt no more than 6 g/day.
- Vitamin D 10 µg/day for adults; folate 400 µg supplement pre-conception and through the first trimester; calcium 700 mg/day adults.
Worked example
A snack supplies 60 g carbohydrate, 25 g protein and 20 g fat. Energy = (60 × 17) + (25 × 17) + (20 × 37) = 1020 + 425 + 740 = 2185 kJ (2185 ÷ 4.184 ≈ 522 kcal). Energy from fat = 740 ÷ 2185 = 33.9%. Reasoning: the snack is inside the 35% fat guideline, but that figure says nothing about saturates or about the rest of the day, so the whole diet must be assessed, not one meal.
Traps that cost marks
- Quoting the RNI as the minimum for everyone, or comparing a group mean with an RNI.
- Confusing grams of fat with percentage of energy from fat.
- Forgetting salt = sodium × 2.5.
- Accepting claims such as 'no added sugar' or 'light' as nutritional guarantees.