Being fat could lead to even more cancers than previously thought, experts have warned.
Researchers have linked being overweight or obese to eight more different types of cancer.
Having excess body fat can increase a middle-aged adult's chance of developing cancers of the stomach, liver, gall bladder, pancreas, ovary, a type of brain tumour called a meningioma, thyroid cancer and the blood cancer multiple myeloma, according to the International Agency for Cancer on Research (IARC) - an arm of the World Health Organisation.
The study, part of the IARC Handbooks of Cancer Prevention programme, saw experts examine more than 1,000 studies of excess weight and cancer risk.
Previous work from the group in 2002, linked excess weight to higher risks of cancers of the colon, oesophagus, kidney, uterus and breast in postmenopausal women.
Now the latest research, published in the The New England Journal of Medicine, has found "sufficient evidence" that eight further cancers are linked to excess body fat.
The 21 independent international experts also found evidence that the higher a person's body mass index (BMI) the greater the cancer risk.
"This comprehensive evaluation reinforces the benefits of maintaining a healthy body weight in order to reduce the risk of several different types of cancer," lead author Dr Beatrice Lauby-Secretan said.
The research also concluded there was "limited evidence" that people of a normal weight had a lower chance of dying from cancer of the prostate, cancer of the breast in men, and a type of lymphoma.
In England, around two-thirds of men and over half of women are overweight or obese.
Dr Graham Colditz, cancer prevention expert based at Washington University School of Medicine in the US, who chaired the IARC group, added: "The burden of cancer due to being overweight or obese is more extensive than what has been assumed.
"Many of the newly identified cancers linked to excess weight haven't been on people's radar screens as having a weight component.
"Lifestyle factors such as eating a healthy diet, maintaining a healthy weight and exercising, in addition to not smoking, can have a significant impact on reducing cancer risk.
"Public health efforts to combat cancer should focus on these things that people have some control over."
Commenting on the study, Caroline Moye, head of the World Cancer Research Fund, said: "This new report further adds to our own evidence that being overweight or obese increases the risk of cancer. In fact, around 25,000 cancer cases could be prevented in the UK if everyone was a healthy weight.
"There are simple lifestyle choices everyone can make to help reduce their cancer risk. For example, going for a 10-minute walk or taking the stairs instead of the elevator can make a difference.
"IARC's report comes at a time when the UK Government has just released their plan to tackle obesity in children. However, their policies do not go far enough if they are reduce obesity rates in this country.
"We urge the Government to look at this new evidence and reconsider including actions such as stricter advertising restrictions."