The risk of bowel cancer is greater if someone is carrying excess fat around the waist, researchers have concluded.
A study found that the chances of a person developing bowel cancer rises by 3% for every extra inch on the waist above a healthy measurement.
Irrespective of overall body mass index (BMI), a big waist circumference is a predictor of bowel cancer, experts claim.
The findings will be presented at an international cancer conference, by the researchers from Imperial College London and the University of Leeds.
The conference focuses on a review of seven existing papers which look at the effect of tummy fat on bowel cancer.
The review provides the strongest evidence so far that the link remains true, even if the rest of the body is in proportion and the person is normal weight or only moderately overweight.
As a guide, a healthy waist measurement is defined as less than 31.5in (80cm) for women, less than 37in (94cm) for white and black men and less than 35in (90cm) for Asian men.
Professor Martin Wiseman, medical and scientific adviser for the World Cancer Research Fund (WCRF), which funded the study, said: "We estimate that more than 2,700 cases of bowel cancer a year in the UK could be prevented through people maintaining a healthy weight."
The results of the review will be presented at WCRF's international scientific conference in London.
The study comes as researchers writing in the European Journal of Cancer said more should be done to prevent people putting on weight, which also increases the risk of bowel cancer.
Dr Esther de Vries, from the Erasmus medical centre in Rotterdam, and colleagues estimated the future burden of colon cancer in seven European countries, including the UK.
They said if people continued to put on weight at the same rate as in the US, then by 2019 rates of bowel cancer would rise between 0.7% (UK) and 3.8%.