A doctor is reviewing the diet of a patient who has been eating the same limited range of foods for several months. The patient's diet is very high in fat and sugar but contains very little protein, iron or vitamin C. Explain the effects this unbalanced diet is likely to have on the patient's health.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
The patient's diet consists mainly of processed snacks and sugary drinks. They rarely eat fruit, vegetables, meat or dairy products.
Model answer (5 marks)
High fat and sugar give excess energy, so the patient is likely to become overweight or obese.
A low protein intake means the body cannot build, repair or replace cells and tissues, leading to muscle wasting and poor recovery.
Insufficient iron causes anaemia – haemoglobin is reduced, so red blood cells cannot carry enough oxygen, resulting in fatigue and shortness of breath.
A deficiency of vitamin C causes scurvy, characterised by bleeding gums, poor wound healing and general weakness.
A low protein intake means the body cannot build, repair or replace cells and tissues, leading to muscle wasting and poor recovery.
Insufficient iron causes anaemia – haemoglobin is reduced, so red blood cells cannot carry enough oxygen, resulting in fatigue and shortness of breath.
A deficiency of vitamin C causes scurvy, characterised by bleeding gums, poor wound healing and general weakness.
Examiner tips
- Use the exact terms from the mark scheme (e.g., ‘excess energy intake’, ‘anaemia’, ‘scurvy’).
- Show the causal chain: high fat/sugar → excess energy → obesity; low protein → impaired tissue repair; low iron → anaemia; low vitamin C → scurvy.
Common mistakes
- Mixing up ‘obesity’ with ‘overweight’ or vice‑versa; both are acceptable but ‘obesity’ is the term the scheme expects.
- For scurvy, forgetting to mention bleeding gums or poor wound healing.
Mark scheme (5 marks)
- High fat/sugar intake leads to excess energy intake / more energy taken in than used
- This can lead to obesity / being overweight
- Lack of protein means the body cannot build / repair / replace cells and tissues
- Lack of iron leads to anaemia / insufficient haemoglobin / red blood cells cannot carry enough oxygen
- Lack of vitamin C leads to scurvy / symptoms such as bleeding gums / poor wound healing
Key terms in this question
unbalanced diet · protein · iron · vitamin C
Related
- All OCR A-Level Biology B — Advancing Biology (H422) revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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