Extra Weight = Extra Cancer Risk
Panel Finds Overweight Is Leading Cause of Cancer, Lists 10 Ways to Cut Risk
Oct. 31, 2007 -- Extra pounds mean extra cancer risk -- even if you're not overweight.
The finding comes from a vast international research effort headed by a panel of experts in obesity, nutrition, cancer, public health, and epidemiology. Funding came from the nonprofit World Cancer Research Fund.
The panel's detailed, 537-page report -- Food, Nutrition, Physical Activity, and the Prevention of Cancer -- can be summed up in one sentence, says panel member W. Philip T. James, MD, DrSc, chairman of the London-based International Obesity Task Force.
"The single message is how much obesity affects cancer risk," James tells WebMD. "The message is absolutely clear as a bell: The relation of cancer to obesity is so robust, it is going to rank close to the smoking problem in America pretty soon."
High-Normal Weight Still Risky
Here's worse news: You don't have to be obese to be at increased risk of cancer.
"The risk is lowest not in the crude normal-weight range. Actually, it is better to be slim, to be lean," James says. "This is what the science shows. Even if you are fortunate in being in the upper-normal range of body weight, you still have cancer risk if you are not doing physical activity."
James says the panel went to great lengths to ensure that their findings were based solely on scientific evidence. To this end, researchers working on the project reviewed every published study on weight and cancer to come up with the 7,000 studies on which they base their conclusions and recommendations.
"You could say, 'We've heard this before.' But you never had this kind of statement backed up by mathematical analysis of 7,000 studies," James says. "This is not a report from a select group of people who have their own biases. It has been done in a three-tier system to make sure it is as rigorous and up to date and savagely analyzed as any group could do."
The panel didn't stop at analyzing cancer risk. It also came up with 10 recommendations for cutting risk.
10 Ways to Cut Cancer Risk
"Risk isn't fate. The evidence clearly shows that risk can be changed," panel member Walter J. Willett, MD, PhD, professor of medicine at Harvard University, said in a news release.