Body weight, physical activity, and diet

You might be able to lower your risk of colorectal cancer by managing some of the risk factors that you can control, like diet and physical activity. 

Weight: Being overweight or obese increases the risk of colorectal cancer in both men and women, but the link seems to be stronger in men. Having more belly fat (that is, a larger waistline) has also been linked to colorectal cancer. Staying at a healthy weight and avoiding weight gain around the midsection may help lower your risk.

Physical activity: Increasing your level of activity lowers your risk of colorectal cancer and polyps. Regular moderate activity (doing things that make you breathe as hard as you would during a brisk walk) lowers the risk, but vigorous activity might have an even greater benefit. Increasing the intensity and amount of your physical activity may help reduce your risk.

Diet: Overall, diets that are high in vegetables, fruits, and whole grains (and low in red and processed meats) have been linked with lower colorectal cancer risk, although it’s not exactly clear which factors are important. Many studies have found a link between red meats (beef, pork, and lamb) or processed meats (such as hot dogs, sausage, and lunch meats) and increased colorectal cancer risk.Limiting red and processed meats and eating more vegetables and fruits may help lower your risk.

In recent years, some large studies have suggested that fiber in the diet, especially from whole grains, may lower colorectal cancer risk. Research in this area is still under way.

https://www.cancer.org/cancer/colon-rectal-cancer/causes-risks-prevention/prevention.html