13 cancer types linked with excess fat

Published in: NEJM 2016
People studied: –

A WHO cancer agency group found sufficient evidence that not having excess body fat lowers the risk of 13 cancers. Proof that losing weight does the same is still being established.

Checked against: PubMed 27557308
Published in: NEJM 2016
Last checked: 30 October 2026

Key takeaway

A working group of the International Agency for Research on Cancer, part of the WHO, reviewed more than 1,000 studies, mostly observational. It found sufficient evidence that not having excess body fat lowers the risk of 13 cancers, adding 8 to the 5 named earlier. Evidence in humans that intentional weight loss lowers cancer risk was judged to be still not established.

At a glance

Type of study: expert review by a WHO cancer agency working group of more than 1,000 studies, mostly observational
Main result: Not having excess body fat lowers the risk of 13 cancers.
Strength of evidence: Long-term or observational studies

What this study does not show

The conclusion is about not having excess body fat, not about losing weight. Studies of weight-loss programmes were sparse, and evidence in humans that losing weight lowers cancer risk is not yet established.

Results from studies in groups of people, mostly in diet and movement programmes. They cannot be promised to any one person. This information is educational and does not replace a consultation with a doctor.