Who this is for: Cambridge IGCSE Coordinated Science (0654) students who can list food groups but lose marks linking each nutrient to its source, function and deficiency disease in diet questions.
What query it owns: how to understand and revise diet in Cambridge IGCSE Coordinated Science.
Why this is safe: this page owns the diet revision-guide angle, while Tutopiya’s Diet subtopic page owns the learning resource and the free Diet quiz owns the practice.

A balanced diet provides carbohydrates, proteins, fats, vitamins, mineral salts, dietary fibre and water in the correct proportions for health, growth and repair. Cambridge IGCSE Coordinated Science (0654) tests whether you can state sources, functions and deficiency symptoms for each group, and design meals for different people (children, athletes, pregnant women). This guide covers the syllabus content and exam wording.

Key takeaways

• Carbohydrates — energy source (starch, sugars); excess stored as fat.
• Proteins — growth and repair; enzymes and antibodies; from meat, fish, eggs, pulses.
• Fats — energy store; insulation; cell membranes; fat-soluble vitamin transport.
• Vitamins — e.g. C (scurvy), D (rickets); mineral salts — e.g. iron (anaemia), calcium (weak bones/teeth).
• Fibre — aids peristalsis; water — solvent, transport, temperature control.
• A balanced diet varies with age, activity and pregnancy.

What is diet in Cambridge IGCSE Coordinated Science?

Diet is the food a person eats. A balanced diet contains all essential nutrients in suitable amounts. Each nutrient has a specific role: carbohydrates and fats mainly supply energy; proteins build tissues; vitamins and minerals support metabolism and prevent deficiency diseases; fibre maintains gut health; water enables chemical reactions and transport.

You can read the full explanation, worked examples and notes on Tutopiya’s Diet subtopic page before you attempt questions.

The core ideas you must master

Nutrient	Main function	Source examples	Deficiency (where tested)
Carbohydrates	Energy	Bread, rice, pasta, fruit	Low energy (not a named disease)
Proteins	Growth, repair, enzymes	Meat, fish, eggs, beans	Kwashiorkor (protein-energy malnutrition)
Fats	Energy store, insulation	Oils, butter, nuts	—
Vitamin C	Connective tissue, immunity	Citrus fruit, vegetables	Scurvy
Vitamin D	Calcium absorption, bones	Sunlight, oily fish, fortified foods	Rickets
Iron	Haemoglobin	Red meat, spinach	Anaemia
Calcium	Bones, teeth, clotting	Milk, cheese, leafy greens	Weak bones / rickets (with vitamin D)
Fibre	Peristalsis, gut health	Whole grains, vegetables	Constipation
Water	Solvent, transport, cooling	Drinks, food	Dehydration

Diet in past-paper wording: command words that matter

Command word / phrase	What the question wants	Typical diet stem
State	Short factual answer	”State the role of protein in the diet.”
Describe	Features of balanced diet	”Describe a balanced diet for a teenager.”
Explain	Cause and effect	”Explain why athletes need more carbohydrate.”
Suggest	Apply to scenario	”Suggest foods for someone with anaemia.”

Worked exam-style stems (how to answer the wording)

1. “State the main functions of carbohydrates, proteins and fats in the diet.” Carbohydrates: energy. Proteins: growth and repair. Fats: energy store and insulation. Reward: one clear function per group.
2. “Describe the symptoms of vitamin C deficiency.” Scurvy: bleeding gums, poor wound healing, weakness. Reward: named disease + symptoms.
3. “Suggest how the diet of a pregnant woman differs from that of an average adult.” More protein, iron, calcium and folate for fetal growth; balanced energy intake. Reward: named nutrients + reason.

When you can recognise the wording instantly, work through the Diet quiz and link to the Alimentary Canal.

How diet connects to the rest of Coordinated Science biology

Diet links to the Alimentary Canal (ingestion and breakdown), Enzymes (digestive enzymes), and Biological Molecules. The Cambridge IGCSE Coordinated Science resource hub links every Animal Nutrition subtopic.

Common mistakes students make

• Saying vitamins provide energy (they do not — carbohydrates and fats do).
• Confusing vitamin D and calcium roles in rickets.
• Omitting water and fibre from balanced-diet lists.
• Naming foods without linking to nutrient function.
• Giving one generic diet for all people regardless of age or activity.

When you need more support

If diet and deficiency questions keep costing marks, work through the Diet quiz, then get focused help from a Cambridge IGCSE Coordinated Science tutor.

Frequently asked questions

Is diet hard in Coordinated Science? The nutrient list is manageable, but marks are lost when students confuse deficiency diseases or omit fibre and water.

What is a balanced diet? Food containing all required nutrients in the correct proportions for health, growth and activity level.

Which deficiency diseases must I know? Scurvy (vitamin C), rickets (vitamin D / calcium), anaemia (iron), kwashiorkor (severe protein deficiency) — check your syllabus tier.

How do I revise diet effectively? Build a nutrient table (function, source, deficiency), practise scenario questions, then take the Diet quiz.

Ready to master Cambridge IGCSE Coordinated Science diet?

Start with the Diet subtopic page, then book a free trial with a Cambridge IGCSE Coordinated Science specialist to turn balanced nutrition into guaranteed marks.

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