Keeping excess weight off your frame may be the best thing you can do to minimize your risk of certain cancers (aside from not smoking). That’s because obesity is increasingly linked to the disease: “It’s on track to overtake tobacco as the leading preventable cause of cancer,” says Therese Bevers, MD, medical director of the Cancer Prevention Center at the University of Texas MD Anderson Cancer Center, in Houston.
Experts still don’t know a lot about the link — including whether being overweight, rather than obese, carries equal risk, and if there’s a better measure out there than the oft-maligned BMI scale. But in a landmark 2003 New England Journal of Medicine study, researchers found that the heaviest women (in this case, those with a BMI of 40 or higher) had death rates from cancer that were 62 percent higher than women with BMIs in the healthy range. In fact, one-third of all cancer deaths in the U.S. each year are linked to poor diet and too-little physical activity, which includes obesity.
Higher levels of insulin, growth factors, inflammation, sex hormones — all are more common in obese patients and are possible explanations for how having a heavier body increases your odds of developing cancer, says Jennifer Ligibel, MD, senior physician at the Susan F. Smith Center for Women’s Cancers at Dana-Farber Cancer Institute, in Boston.
It’s important to remember that obesity isn’t linked to increased risk of every kind of cancer though, says Steven Clinton, MD, PhD, cancer researcher at the Ohio State University, in Columbus. “Endometrial, ovarian, esophageal adenocarcinoma, postmenopausal breast cancer, colon — those are the ones that are most strikingly related to weight,” he says.
If you have more questions about the relationship between obesity and cancer, or you’re wondering if your weight puts you at higher risk, bring it up with your doctor at your next checkup.