Nutrition language and diet-related problems
Distinguish the syllabus terms used to describe diet, metabolism, balanced eating and forms of malnutrition.
Exam scope and assessment notes
This original StudyForA lesson maps Cambridge IGCSE Food & Nutrition 0648 topic 1 for examinations in 2026–2029. These are not Cambridge questions, mark schemes or official grades. The practical examination is a real, centre-administered cooking test with a planning session and assessed preparation, time management, results and quality. These screen-based lessons can teach the theory and help rehearse planning and evaluation, but they cannot provide a kitchen, verify safe food handling or practical skill, replace teacher-supervised cooking, award the practical mark, or guarantee an exam grade. Follow your centre’s instructions, local food-safety rules, medical advice and emergency procedures. Any meal examples are for syllabus practice, not individual dietary or medical advice.
Before you begin
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Before you start: What does a person consume over time?
What you will learn
- Use diet and balanced diet accurately
- Distinguish undernutrition from overnutrition
- Explain how inadequate nutrient supply can lead to deficiency disease
- Use metabolism in the context of body processes
Terms that describe diet
Diet means the food and drink a person habitually consumes; it does not automatically mean a weight-loss plan. A balanced diet supplies the nutrients and energy needed by a particular person in appropriate amounts and proportions. Requirements vary with age, activity, health and other circumstances, so a menu cannot be judged from one food alone.
Metabolism is the total of chemical processes in the body. Malnutrition is a broad term for poor nutrition arising from an unbalanced or inadequate intake, including undernutrition and overnutrition. Undernutrition describes insufficient energy or nutrients; overnutrition describes excessive intake, often in relation to energy or particular nutrients. A person’s health cannot be diagnosed from a short menu example.
Deficiency and careful conclusions
A deficiency disease can develop when the diet does not supply enough of a particular essential nutrient over time. The nutrient, amount, duration and a person’s circumstances matter. A single meal cannot establish a deficiency or diagnose illness.
In an exam answer, define the term first, then apply it to the evidence. Do not use malnutrition as a synonym only for hunger, or assume every person eating a high-energy meal is overnourished. Nutrition questions need context and qualified conclusions.
Sources for this lesson
Pause and explain
Which statement best distinguishes undernutrition and overnutrition?
Worked example
A case study describes a teenager whose diet contains enough energy but very few fruit or vegetables. Explain why energy intake alone cannot show that the diet is balanced.
Show the worked solution
- A balanced diet is about more than energy.
- Fruit and vegetables can contribute vitamins, minerals, water and dietary fibre.
- The case gives limited information, so it cannot diagnose a deficiency or describe the whole diet.
Answer Energy alone does not establish balance: the diet must also provide a suitable range of nutrients. The case may suggest a limited source of some nutrients and fibre, but the full diet and health context would be needed before drawing a conclusion.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A menu records one meal with lots of energy but little variety. What can you conclude about balance, and what information is still missing?
Give me a hint
Separate energy from the full range and amount of nutrients across a person’s diet.
Compare my reasoning
- State that energy is only one part of a balanced diet.
- Identify that variety may affect other nutrient sources.
- Name missing evidence such as the full diet, needs and health context.
The meal alone cannot show whether the overall diet is balanced. Energy is only one consideration; the rest of the person’s food intake, portion amounts, needs and context are not given, so a health diagnosis would be unjustified.
Look for these in your work
- Distinguishes energy from balance
- Uses the time span of the full diet
- Avoids diagnosing from limited evidence
A learner defines metabolism as “the food a person eats”. Correct the definition and explain why it matters in this course.
Give me a hint
Focus on chemical processes in the body, rather than the food itself.
Compare my reasoning
- Replace the incorrect definition with the total chemical processes in the body.
- Distinguish metabolism from diet.
- Use the corrected term in a sentence about nutrients or energy.
Metabolism is the total of chemical processes in the body. Diet is the food and drink a person usually consumes. Keeping the terms separate helps explain how nutrients from food are used rather than confusing the food with the body processes.
Look for these in your work
- Defines metabolism accurately
- Distinguishes it from diet
- Explains why precise terminology helps
Two people eat different lunches. One is described as malnourished. What further evidence would you need before explaining the term in this case?
Give me a hint
Consider the person’s overall pattern and whether the intake is insufficient or unbalanced.
Compare my reasoning
- Ask about usual intake over time, not one lunch.
- Consider energy and nutrient adequacy in relation to individual needs.
- Avoid assuming a diagnosis; use reliable assessment or professional evidence.
A single lunch is not enough. The usual diet over time, nutrient and energy intake relative to needs, and reliable health or assessment information would help distinguish undernutrition, overnutrition or another imbalance. The label should not be diagnosed from a menu snapshot.
Look for these in your work
- Requests evidence over time
- Considers needs and nutrient range
- Avoids unsupported diagnosis
Common mistakes
- Defining diet only as a weight-loss plan
- Treating undernutrition and overnutrition as the same condition
- Diagnosing a deficiency from one meal
What can you explain now?
Which statement best distinguishes undernutrition and overnutrition?
Compare with the explanation
They describe insufficient and excessive intake respectively
Use the syllabus concept, connect it to the stated evidence or needs, and explain any limit on your conclusion.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
How do malnutrition, undernutrition and overnutrition relate to one another?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.