A population based, case-control study in JAMA Oncology looked at the connection between being overweight and colorectal cancer. The German researchers examined height and weight in 10-year increments starting at age 20, comparing 5,635 people with colorectal cancer to 4,515 subjects in a control group.

The odds of colorectal cancer increased significantly over the decades as people carried excess weight compared with participants who remained within a normal weight range. Comparing quartiles of number of years lived overweight or obese, the first quartile presented a 25 percent greater risk of colorectal cancer while the fourth quartile presented a 154 percent increase in risk compared to subjects with normal weight.

Nearly two-thirds of Americans are overweight and more than one-third are obese. Everyone knows obesity is unhealthy. Most are aware it increases the risk of diabetes. Now we can add colorectal and most likely other cancers to the list of health issues associated with excess body weight.

The reasons so many Americans are overweight are simple: We eat poor quality food and we don’t exercise enough. In particular, we eat too many refined foods. If we simply eliminated those, we could start to reverse the obesity epidemic that has gripped our country.

And I can’t stress the importance of exercise enough. It can benefit any health condition, including obesity. Simply walking 30 minutes a day will increase the body’s metabolic capabilities.