Around 6,000 cases of cancer in women are due to the fact the patients are overweight or obese, a new study claims.
The findings, published online in the British Medical Journal (BMJ), show two thirds of these cancers affect the womb or breasts of middle-aged and older women.
Half of all womb lining cancers and cases of one type of oesophagus cancer in this group of women were caused by excess weight, it added.
The research by the charity Cancer Research UK looked at the factors behind 45,000 cancers occurring in more than a million women over seven years.
Scientists matched Body Mass Index (BMI) data against cancer incidence to identify the risk from being overweight.
Chief researcher Dr Gillian Reeves, from Oxford University, said: "Based on our findings, we estimate that being overweight or obese accounts for around 6,000 out of a total 120,000 new cases of cancer each year among middle-aged and older women in the UK.
"Our research also shows that being overweight has a much bigger impact on the risk of some cancers than others. Two thirds of the additional 6,000 cancers each year due to excess weight or obesity would be cancers of the womb or breast."