Food and Nutrition
Food and Nutrition
This domain tests how nutrients, meal planning, preparation, preservation and food safety connect. Expect questions that ask you to name nutrient functions, adapt a meal to a budget or health need, explain a preservation method, and identify hygiene errors in a scenario.
Core nutrient rules
- Carbohydrates supply energy; excess is stored as fat. Fibre (a non-digestible carbohydrate) prevents constipation and lowers risk of some diseases.
- Proteins build and repair tissue; animal sources (fish, eggs, milk, meat) are complete, while most plant sources (mahangu, sorghum, cowpeas, groundnuts) are incomplete or limiting in one amino acid, so combine cereals with legumes.
- Fats provide concentrated energy and carry vitamins A, D, E and K; unsaturated plant oils are preferable to hard fats.
- Vitamins and minerals are micronutrients: vitamin A (growth, vision, immunity), vitamin C (collagen, iron absorption), iron (haemoglobin), calcium (bones, teeth), iodine (thyroid). Water is a nutrient too.
Meal planning and preparation
A balanced meal has variety, adequacy, moderation and balance, and fits cost, season, culture and health. Include energy food, body-building food and protective food. Cook vegetables quickly in little water; water-soluble vitamins (B and C) leach into cooking water and are destroyed by heat, light and oxygen. Protein coagulates and becomes tough with overcooking.
Safety and preservation
Keep clean, separate raw and cooked food, cook thoroughly, and chill below 5°C; the danger zone is roughly 5–60°C. Drying, salting, fermenting, canning and freezing slow or stop microbe growth by removing water, lowering water activity, raising acidity, excluding air or applying heat.
Worked example
Plan a low-cost lunch: mahangu porridge + boiled cowpeas + spinach and tomato + a spoon of groundnut paste. Reasoning: porridge gives energy and fibre; cowpeas add protein, iron and fibre; tomato's vitamin C helps absorb plant iron; groundnuts add fat and energy. Steam spinach briefly rather than boiling it for long.
Traps
Do not claim a single food is 'complete' for everyone; do not store cooked food in the danger zone; do not say freezing kills bacteria (it only stops growth); do not forget that fruit juice lacks whole-fruit fibre.