Obesity could soon be the new smoking - cancer risk study shows
Obesity could soon be the new smoking, health professionals have warned.
The claim comes as new research reveals that, as smoking rates decline and obesity levels increase, obesity could overtake smoking as the biggest cause of avoidable cancer.
The Cancer Research UK study ranked the causes of the disease: smoking, excess weight, overexposure to UV radiation from the sun and sunbeds, drinking alcohol, eating too little fibre, and outdoor air pollution.
Nearly 40% of cancers could be avoided through changes in lifestyle, including quitting smoking and reducing weight, they found.
According to 2015 figures - the latest available - more than 135,500 cases of cancer a year (37.7% of the total diagnosed) could be prevented. This rises to 41.5% in Scotland.
Smoking remains the biggest preventable cause, responsible for around 32,200 cases of cancer in men (17.7% of all male cancer cases) and around 22,000 (12.4%) in women.
Being overweight or obese is the second biggest preventable cause of cancer, with around 22,800 (6.3%) cases.
Cancer Research UK chief executive Sir Harpal Kumar said: "Obesity is potentially the new smoking, if we're not careful.
"My sense would be it'll be some time in next couple of decades that we'll see those two switch around."
Obesity causes 13 types of cancer, including bowel, breast, kidney and womb.
Also, more than one in 20 cases could be prevented by maintaining a healthy weight.
Dr Katrina Brown, Cancer Research UK's statistical information and risk manager and the study's lead author, said the public would eventually come to understand the dangers of obesity, just as they eventually did with smoking.
Dr Brown added: "People regard being large as increasingly normal - that is a shift in cultural norms and acceptability, so we need to not only convey the message about the health risks, but also that our population is getting larger."
In terms of other preventable causes of cancer, overexposure to UV radiation from the sun and sunbeds causes around 13,600 cases of melanoma skin cancer a year (3.8% of all cases), while drinking alcohol causes around 11,900 cases and eating too little fibre is responsible for around 11,700.
Sir Harpal added: "Leading a healthy life doesn't guarantee that a person won't get cancer, but it can stack the odds in your favour."
The research is published in the British Journal of Cancer.
