7.1 Diet
- Syllabus
- 0610–2026–2027
- Topic
- 7.1
- Level
- —
A balanced diet contains all the required nutrients and other dietary components in the correct amounts and proportions for a person's needs.
| Required component | Main contribution |
|---|---|
| carbohydrates and fats | energy |
| proteins | growth and repair |
| vitamins and mineral ions | maintain particular body processes and structures |
| fibre | supports movement through the alimentary canal |
| water | solvent, transport medium and reaction environment |
The correct amount is not identical for everyone. Energy and nutrient requirements vary with age, sex, body size, activity, pregnancy and health.
Too little of a component can cause deficiency; too much energy intake relative to use can increase fat storage and body mass. Balance therefore means adequacy without harmful excess.
A balanced diet is not simply eating equal amounts of every food group or avoiding all fat. It supplies different components in proportions matched to need.
Learn each dietary component as a source–function pair: where it comes from and why the body needs it.
| Component | Principal sources | Importance |
|---|---|---|
| carbohydrates | bread, rice, pasta, potatoes and cereals | main energy source for respiration |
| fats and oils | butter, vegetable oils, nuts, seeds and fatty foods | concentrated energy source and store; thermal insulation and organ protection |
| proteins | meat, fish, eggs, dairy foods, beans and pulses | amino acids for growth and repair; making enzymes and other proteins |
| Component | Principal sources | Importance |
|---|---|---|
| vitamin C | citrus fruits and fresh fruit/vegetables | healthy connective tissue, gums and skin; wound healing |
| vitamin D | oily fish, egg yolk, liver and fortified foods; also made in skin using sunlight | calcium absorption and strong bones/teeth |
| calcium ions | milk and other dairy foods; leafy green vegetables | formation and maintenance of bones and teeth |
| iron ions | red meat, liver, beans and leafy green vegetables | making haemoglobin for oxygen transport |
| Component | Principal sources | Importance |
|---|---|---|
| fibre (roughage) | wholegrain cereals, fruit and vegetables | adds bulk and helps food/faeces move through the alimentary canal, reducing constipation |
| water | drinks and water-rich foods | solvent and transport medium; needed for reactions and temperature control |
Vitamins and mineral ions do not provide energy. Fibre is not digested for energy in this syllabus; it helps movement through the gut.
Scurvy is caused by vitamin C deficiency. Rickets is caused mainly by vitamin D deficiency, which reduces calcium absorption; insufficient dietary calcium can also contribute.
| Deficiency disease | Missing nutrient or cause | Consequence | Typical signs |
|---|---|---|---|
| scurvy | too little vitamin C | weak connective tissue and poor repair | bleeding gums and slow wound healing |
| rickets | too little vitamin D, often with inadequate calcium or little sunlight | bones do not mineralise normally | soft, weak or bowed bones and poor skeletal development |
Vitamin-C-rich fruit and vegetables prevent scurvy. Vitamin D from diet and safe sunlight exposure, together with adequate calcium, supports normal bone development and helps prevent rickets.
Vitamin D is linked to rickets because it enables efficient calcium absorption; naming calcium alone without explaining vitamin D misses the principal syllabus deficiency link.
Do not swap the diseases: iron deficiency causes anaemia, protein deficiency can cause kwashiorkor, vitamin C deficiency causes scurvy and vitamin D deficiency causes rickets.