You may want to start paying more attention to your waistband.

A new report says excess body weight accounts for 7 percent of cancer cases in the United States.

The study, published in JAMA Oncology, found that from 2011 to 2015, among people over age 30, 4.7 percent of cancers in men and 9.6 percent of cancers in women were attributed to excess weight.

There is convincing evidence that obesity is linked to an increased risk for 13 cancers, including endometrial cancer, postmenopausal breast cancer and liver cancer.

“The mechanisms underlying the link between obesity and cancer are still not fully understood,” said Moffitt Cancer Center epidemiologist Dr. Kathleen Egan. “Obesity, particularly visceral fat, leads to physiological changes and a range of effects that contribute to cancer.” Those effects include insulin resistance, chronic inflammation and an unhealthy gut microbiome.

Dr. Egan says things like a sedentary lifestyle, unhealthy diet and excessive alcohol intake can contribute to cancer risk because they promote obesity.

The highest rates of weight-associated cancer are in the South and Midwest. More than 8 percent of cancers in Texas and Washington D.C. are associated with obesity, but only 5.9 percent in Hawaii. In Florida, 6.5 percent of cases were linked to high body weight.

“Obesity may be as important as smoking as a contributor to overall mortality and cancer, and may even surpass it,” said Dr. Egan.

While smoking prevalence has decreased, obesity is on the rise, and researchers expect to see an increased number of cancer cases attributed to excess weight gain in the coming years.