Cancer preventionEvidence-basedLesson 30 of 32

Diet, weight and cancer risk

A meaningful share of cancers are linked to modifiable factors — the evidence is clearer than the headlines suggest.

4 min+20 XP

What the evidence supports

Excess body fat is linked to at least 13 cancers. Alcohol is a group 1 carcinogen with risk rising from the first drink. Processed meat is also classified group 1, though the absolute risk increase per serving is small.

Protective patterns

High fibre intake is consistently associated with lower colorectal cancer risk. Diets rich in vegetables, fruit, whole grains and legumes perform best across studies — no single 'superfood' matches the pattern effect.

Keeping perspective

Relative risk headlines exaggerate. What matters is your habitual pattern over years: body weight, alcohol, fibre, physical activity and not smoking account for the large majority of modifiable risk.

Key takeaways

Excess body fat is linked to at least 13 cancers.
Fibre-rich patterns lower colorectal risk.
Habitual patterns matter far more than single foods.

Check your understanding

1 question · answer to earn XP

1. Which factor is linked to the widest range of cancers?

Evidence & sources

This lesson reflects guidance from recognised health bodies and peer-reviewed research.

For education purposes only — not intended to diagnose, treat or replace medical advice.