Cancer risk factors

What are the links between lifestyle and cancer risk?

Our analysis of global research shows that around 40% of cancers are preventable. Eating a healthy diet, being more active each day and maintaining a healthy weight are, after not smoking, the most important ways you can reduce your cancer risk.

Obesity and weight

Being overweight or obese increases the risk of 12 types of cancer.


Drinking alcohol increases the risk of six cancers, including colorectal (bowel) and breast.

Poor diet

Eating food that is high in fat or sugar can make you gain weight, and there is strong evidence that being overweight or obese increases the risk of 12 cancers. However, diets that are high in wholegrains, vegetables and fruit may protect against certain cancers. 

Red and processed meat

Eating too much red meat and any processed meat increases cancer risk. 

Being inactive

We have strong evidence that being active (moderate and vigorous exercise) reduces the risk of three cancers: colorectal, breast (post-menopausal) and womb. We have strong evidence that being vigorously physically active reduces the risk of pre-menopausal breast cancer.


Tobacco is the biggest cause of cancer around the world.

Sun and UV

Sunbeds, sunbathing and too much exposure to sunlight can cause cancer. 


Approximately 15% of cancers globally are caused by infections.

HRT and the Pill

HRT and hormonal contraception have been linked with certain cancers.

Inherited genes and family history

Only about five to ten per cent of all cancers result from specific inherited genes.  

Radiation and pollution

Follow the link for information on mobile phones, X-rays, microwaves and other types of radiation.

Myths and controversies

We explore the rumours, fiction, media reports and urban legends about whether everyday products increase cancer risk. 

Our Continuous Update Project

Our Third Expert Report, Diet, Nutrition, Physical Activity and Cancer: a Global Perspective, summarises all the strong evidence from our Continuous Update Project (CUP) – our ongoing programme to analyse global research on how diet, nutrition and physical activity affect cancer risk and survival.