The average man would need to gain only about 25 pounds over what’s considered his normal weight to increase his cancer risk
Pack on the pounds and you might gain more than just a spare tire: Excess weight raises your cancer risk more than previously thought, new research suggests.
Prior studies have already linked higher weights to an increased risk of 5 types of cancer: colon, esophagus, kidney, breast, and uterine (the last two for women only.)
Now, after analyzing more than 1,000 studies that looked at excess weight and cancer risk, researchers from the International Agency for Research on Cancer (IARC) have added 8 more types of cancer to the list.
For men, excess weight—which the researchers defined as a body mass index (BMI) of above 25, meaning overweight or obese—raised the risk of developing 7 additional types of cancer: cancers of the stomach, liver, gallbladder, pancreas, brain, thyroid and bone marrow. (Women with extra pounds also faced one more risk—an increased chance of developing ovarian cancer.)
How much it spiked your risk depended on the cancer: For instance, people with the highest BMIs were 10 percent more likely to develop thyroid cancer and 80 percent more likely to get diagnosed with stomach cancer than those with normal BMIs.
The average man would need to gain only about 25 pounds over what’s considered his normal weight to increase his risk, says Graham Colditz, M.D., chair of the IARC Working Group.
That might be because obesity can cause changes to your metabolism and hormones in a way that causes chronic inflammation—and the evidence linking this to cancer is strong.
One important note: The researchers used BMI to measure excess fat, which isn’t a perfect tool.
BMI only takes into account height and weight. That means a guy with lots of muscle mass may be considered obese, even though his wouldn’t have much extra fat at all. (That’s Why Dwayne ‘The Rock’ Johnson Is Officially Obese).
Still, in this case, where the researchers were analyzing over 1,000 previously-performed studies, grouping by BMI was the best, most consistent approach.
And it does tend to accurately identify the majority of those who actually have excess fat as overweight or obese, Dr. Colditz says.
So what’s your move if you’re carrying around extra pounds?
The good news is that reduction in weight, even by 5 percent, can begin to lower cancer risk, he says. (These 10 Ways to Lose Weight Without Even Trying can help.)
And if you’re currently at a healthy weight? Make it your business to stay that way.
“Avoiding more weight gain will certainly avoid further increase in risk of cancer,” he says. “The first approach should be to keep weight constant.”