Explain how a diet high in saturated fat can lead to a person suffering a heart attack.

Eduqas GCSE Biology — 3.4 Non-communicable diseases in humans · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Saturated fat increases blood cholesterol levels, which builds up to form plaques or fatty deposits in the walls of the coronary arteries.
These plaques narrow the lumen of the coronary arteries, restricting blood flow to the heart muscle.
A blood clot (thrombus) can then form and completely block the coronary artery, cutting off the blood and oxygen supply to the heart muscle.
The loss of oxygen causes the heart muscle to die or stop contracting, leading to a heart attack.

Examiner tips

Use the exact sequence of events: saturated fat → ↑ cholesterol → plaque formation → artery narrowing → clot → loss of blood supply → heart muscle death.
Mention both plaque build‑up and clot formation to cover all four marking points.

Common mistakes

Failing to link saturated fat to increased cholesterol.
Omitting the clot formation step or describing it as a general blockage rather than a thrombus.
Using vague terms like "fatty deposits" without specifying plaques in coronary arteries.

Mark scheme (4 marks)

Saturated fat increases blood cholesterol levels
Cholesterol builds up to form plaques / fatty deposits in the walls of the coronary arteries
Plaques narrow the lumen of the coronary arteries, restricting blood flow to the heart muscle
A blood clot (thrombus) can form and completely block the coronary artery, cutting off the blood / oxygen supply to the heart muscle, causing the heart muscle to die / stop contracting

Key terms in this question

saturated fat · heart attack