Being overweight and drinking too much alcohol increase an individual's risk of getting cancer, according to a major report being released today.
The World Cancer Research Fund (WCRF) survey issues a stark warning about the clear links between lifestyle, diet and exercise and the risk of developing the often fatal disease.
And it states that there is a direct relation between the extent of excessive weight and alcohol intake and the likelihood of falling victim to cancer.
Chairman of the survey committed, Professor Sir Michael Marmot
Most of what the survey recommends is in line with what health experts, including governments and the World Health Organization, have long been advising - that diets based on fruits, vegetables and whole grains and that go easy on red meats, dairy products, alcohol and fats protect against heart disease, diabetes and cancer.
The groups make keeping a healthy weight their main recommendation to reduce the risk of cancer.
"Be as lean as possible within the normal range of body weight," the 400-page WCRF report reads. That means keeping a body mass index, it said, of between 21 and 23. BMI is a calculation of height to weight, and the normal range is usually considered to be 18 to 25, with anything over 25 being overweight.
Exercise is also key. "Be physically active as part of everyday life," is the second of 10 recommendations made by the expert panel. The recommendations also include eating mostly plant foods, such as fruits, vegetables and grains, avoiding calorie-dense foods such as sugary drinks, and limiting red meat, alcohol and salt.
Survey chair Professor Sir Michael Marmot, professor of epidemiology and public health at University College London, said he was surprised at the strength of the link it established between weight and cancer risk.
And he said there was a "very clear message" from its findings for the general population: "Firstly, as you enter adulthood, don't put on weight. Secondly, if you are already overweight, it is likely that losing weight would lower your risk."
The direct link between increased weight and increased cancer risk was even stronger than that linking cigarettes with cancer, he suggested.
"With smoking, we know that if you smoke you increase your risk, but most smokers in the end don't get cancer, so it's not a one-to-one relation," he explained. "With obesity and overweight, it is very clear and it is a graded phenomenon. The more overweight you are, the more obese you are, the higher the risk of cancer."