Food and Nutrition Knowledge and Understanding
What you must know
This domain tests the scientific foundations behind food: the macronutrients (carbohydrates, proteins, fats) and micronutrients (vitamins, minerals), their functions, energy values and dietary sources; the principles of digestion and absorption; the role of water and fibre; and the main diet-related conditions such as obesity, type 2 diabetes, coronary heart disease, dental caries and iron-deficiency anaemia. You should also understand the components of a balanced diet, reference intakes, and the guidance behind public healthy-eating models. Energy values are a frequent source of marks: carbohydrate and protein supply roughly 4 kcal per gram, fat roughly 9 kcal per gram, alcohol roughly 7 kcal per gram, and fibre is commonly counted at about 2 kcal per gram.
Traps to watch
Questions often confuse nutrient function with nutrient source, or mix up fat-soluble vitamins (A, D, E, K) with water-soluble ones (B group, C). Watch for statements that overstate a single nutrient as a cure, or that treat all fats as harmful - unsaturated fats are essential. Another trap is confusing deficiency with excess: vitamin A deficiency causes night blindness, but excess in pregnancy is harmful. Read whether a question asks for energy-providing nutrients (only the macronutrients and alcohol) or for all nutrients.
Worked example
A 50 g portion of a food contains 20 g carbohydrate, 5 g protein and 10 g fat. Energy = (20 × 4) + (5 × 4) + (10 × 9) = 80 + 20 + 90 = 190 kcal. The remaining 15 g is largely water and fibre, which contribute little or no significant energy in this calculation. Rule of thumb: always apply 4-4-9 to carbohydrate, protein and fat respectively before adding alcohol at 7 kcal/g where present.