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Obesity: A Growing Risk For Cancer

Many people know that being overweight can increase the chances of developing some serious health problems like heart disease and diabetes. But there’s another health risk from too many pounds that is often overlooked: Cancer. And it’s a risk that shouldn’t be ignored.

“Obesity will probably overtake smoking as the leading cause of cancer in the future,” said Rishi Jain, MD, MS, DABOM, a medical oncologist at Fox Chase Cancer Center. “Some estimate it could happen in the next 20 to 25 years. Unfortunately, most people don’t realize that obesity has a really strong link to cancer.”

The cancer-obesity link

According to the National Health and Nutrition Examination Survey, almost 70 percent of U.S. adults are overweight or obese. A body mass index (BMI) of 25.0 to 29.9 is considered overweight; 30.0 to 39.9 is considered obese; and 40 and higher is considered severely obese.  

The American Cancer Society (ACS) estimates that about 8 percent of all cancers in the U.S. are caused by excess weight, as well as about 7 percent of all cancer deaths.

Being overweight or obese can impact cancer risk in multiple ways. Among them:

Chronic, low-level inflammation is common in people who are obese. This inflammation can, over time, trigger DNA damage that may lead to cancer. One example: Chronic inflammation by gastroesophageal reflux (GERD) or Barrett’s esophagus is a likely cause of esophageal cancer.

  • Obesity is also linked to increased levels of insulin and insulin-like growth factor-1, and high levels of both may promote the development of colon, kidney, prostate, and endometrial cancer.
  • Fat tissue produces excess estrogen. Elevated levels of this hormone have been tied to a raised risk of several cancers, including breast, endometrial, and ovarian cancers.
  • Fat cells produce hormones that may stimulate or inhibit cell growth, which may boost the chances of developing cancer.

This increased likelihood of cancer can impact people of all ages who are overweight or obese.

“Obesity-related cancers are increasing in younger populations,” Jain said.

The risk of colorectal, endometrial, pancreatic, and gallbladder cancers in millennials is about double what it was for Baby Boomers at the same age.

How to reduce your risk

Maintaining a healthy weight is a good goal. But if you are carrying too many pounds, you don’t have to reach your ideal weight to decrease your health risks, including your risk for cancer.

“Patients who are overweight don’t realize that even losing 5 to 10 percent of their weight, while it might not seem like enough, has been shown to improve overall health and improve diabetes, blood pressure, and markers of cancer risk,” Jain said.

To help shed pounds, Dr. Jain suggests being physically active and eating a diet rich in whole grains, vegetables, fruits, and beans. Limiting fast food, processed food, red meat, and sugary and alcoholic drinks can make a big difference too. And if lifestyle and diet changes don’t do the trick, more aggressive treatments including weight loss medications or bariatric surgery may be necessary.

“Once you start eating a more plant-based, whole-food diet, in most cases weight loss would follow,” Jain said. “Being physically active and having a good quality diet in and of itself is important. Even a small amount of weight loss can make a big difference.”

Learn more about other ways to reduce your cancer risk.

Also read: Can Your Weight Affect Your Risk of Getting Cancer.