The #1 Habit to Break to Reduce Colorectal Cancer Risk

Colorectal cancer is becoming an increasingly common diagnosis, with rates rising, especially among younger adults. In fact, it is the third most common cause of cancer in the world. This form of cancer affects the colon and rectum, which are critical parts of the digestive system, and it often develops silently before showing symptoms. While medical advancements have significantly improved treatment options, prevention is more important than ever. Some risk factors, such as genetics, are beyond our control, but many are associated with lifestyle choices, offering opportunities to reduce risk. Research suggests that approximately half of colon cancer cases could be prevented by addressing modifiable risk factors, such as dietary habits. Here, we’ll explore how eating more fiber is a powerful yet simple change you can make to help protect yourself from developing colon cancer. We’ll break down what fiber does for your body, why it’s so important for your colon health and how to include it more easily.

Not eating enough fiber is a habit many of us have without even realizing it—and it’s one that could raise your risk of colorectal cancer. Fiber, also known as dietary fiber, is a type of carbohydrate found in plant-based foods like fruits, vegetables, whole grains, nuts, seeds and legumes. Unlike other types of carbs, fiber isn’t broken down by your body. Instead, it passes through your digestive system, helping to keep everything moving smoothly and supporting gut health. When you skimp on fiber, your colon misses out on these benefits, which can make it more vulnerable to changes that can lead to cancer.

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Research suggests that a high-fiber diet can play a protective role against colorectal cancer. In fact, some research suggests that a 10% reduction in colorectal cancer risk may be observed for a 10-gram per-day intake of dietary fiber. And a study published in the American Journal of Clinical Nutrition showed that, after analyzing data from over 100,000 people, those who had a higher soluble fiber intake had a 59% reduced risk of developing colorectal cancer compared to those with lower intake levels.

“One important type of fiber is resistant starch, found in foods like green bananas, legumes and [cooked and] cooled potatoes,” shared Johannah Katz, M.A., RD, an Orlando-based registered dietitian. “Fiber, including resistant starch, acts as a prebiotic, feeding beneficial gut bacteria and producing short-chain fatty acids, like butyrate, that play a key role in reducing inflammation, protecting the gut lining and promoting healthy cell growth,” said Katz. “Butyrate also helps repair DNA damage in the colon cells, helping to prevent mutations that could lead to cancer,” Katz added. “Certain types of fiber are able to be fermented by the gut which can result in the release of anti-inflammatory compounds,” Amanda Godman, M.S., RD, CDN, registered dietitian and owner of Amanda Godman Nutrition, shared.

Additionally, fiber adds bulk to your stool. “More bulky stool may help flush out waste and potential carcinogens,” Katz added. Fiber also binds to potentially harmful compounds, like certain bile acids, and helps move waste through your system more quickly, cutting down the time these substances stay in your body.

A paper published in the International Journal of Molecular Sciences notes that the foods you choose to eat on your higher-fiber diet may help reduce your colorectal cancer risk. This is because of the other nutrients you consume, especially if you are increasing your vegetable intake. Fiber is commonly found in vegetables, which are packed with antioxidants like resveratrol, polyphenols, and phytoestrogens. These natural compounds help your body by reducing harmful oxidative stress, calming inflammation and aiding in the repair of damaged cells.

Unfortunately, most Americans are not meeting the recommended daily fiber intake. According to the Academy of Nutrition and Dietetics, women should aim for at least 25 grams of fiber per day, while men should aim for 38 grams.  However, the average American only consumes about 15 grams per day.

How To Eat More Fiber Every Day

Eating more fiber every day can be simple with a few practical adjustments to your meals. “The simplest way to include more fiber in your diet is to add color to your plate,” shared Alexandria Hardy, RDN, LDN, registered dietitian and owner of Pennsylvania Nutrition Services. “Aim to eat the rainbow each week when you go grocery shopping—red tomatoes, oranges, yellow squash, pears, blueberries and eggplant. It’s an easy visual cue when shopping for produce,” she added. 

Another tip for increasing fiber intake? “Eat more beans and lentils,” explained Supriya Rao, M.D., DipABOM, DipABLM, a board-certified gastroenterologist. “Beans and lentils are high in fiber and other nutrients, and are an easy way to increase the fiber in your meal,” Rao added. 

Finally, Katz suggested swapping some of the low-fiber foods in your eating pattern for higher-fiber alternatives to increase fiber intake in a sustainable way. “Replace white bread or tortillas with whole-grain or flaxseed wraps—there are so many high fiber tortillas out there these days. Try swapping white pasta with legume or whole-wheat options, and swap white rice with cauliflower rice, quinoa or lentils,” Katz offered. “For breakfast, steel-cut oats, bran cereals or other higher fiber varieties can be enjoyed instead of high-added-sugar, low-fiber options,” per Katz.

Other Tips For Supporting Colon Health

Along with eating more fiber, there are other habits you can adopt that may help reduce your colon cancer risk. According to Katz, some tips for supporting colon health include:

Get Regular Screenings & Checkups

Even without symptoms, regular colonoscopy screenings can help detect precancerous polyps before they turn into cancer (these polyps often take 10 to 15 years to progress, so catching them early is super important). The American Cancer Society recommends regular colonoscopy screenings at age 45 instead of 50, due to rising rates of colorectal cancer in younger adults. Those with a family history or genetic predisposition may need earlier or more frequent screenings.

Limit Ultra-Processed Meat

Diets high in ultra-processed meats (such as bacon, sausage and deli meats) have been linked to colon cancer due to the nitrosamines, heme iron and inflammatory compounds they contain. The American Institute for Cancer Research recommends limiting red meat to 18 ounces per week for cancer risk reduction, regardless of how processed it is. The same institute suggests that for processed meat, every 50 grams (about one hot dog or two slices of ham) eaten daily raises the risk of colorectal cancer by 16 percent.

Optimize Vitamin D Levels

Low vitamin D is consistently associated with higher colorectal cancer risk, likely due to its role in immune regulation and cell growth. Studies suggest maintaining vitamin D levels above 40-50 ng/mL may offer protection, making sun exposure, fatty fish and supplementation important for those at risk. Talk to your healthcare team for more information on your vitamin D levels. 

Incorporate Protective Probiotics

Regular consumption of fermented dairy, such as kefir and yogurt, has been linked to a lower risk of colon cancer. These probiotic-rich foods help enhance gut health, reduce inflammation, bind bile and metabolize acids, and produce anti-cancer metabolites that help strengthen the gut lining and regulate immune responses.

The Bottom Line

Adopting a fiber-rich diet may be a powerful step toward reducing your risk of colorectal cancer. Fiber not only supports digestion but also plays a critical role in maintaining overall colon health by reducing inflammation, promoting the growth of beneficial gut bacteria, and flushing out harmful compounds. Coupled with the numerous antioxidants and other nutrients found in fiber-rich foods, this approach can help protect you against cancer-causing changes in the colon. By making simple yet impactful dietary changes—such as incorporating more fruits, vegetables, beans and whole grains into your meals—you may actively contribute to lowering your cancer risk while also improving your overall well-being.

However, it’s equally important to complement a healthy diet with other preventative measures. Regular screenings remain one of the most effective ways to detect precancerous changes early. Additionally, limiting processed meat consumption, optimizing vitamin D levels and incorporating probiotic-rich foods like kefir and yogurt can all further support a healthy colon. While colorectal cancer rates are rising, especially among younger populations, you have the power to take control of your health. Through informed choices and proactive habits, you may be able to potentially reduce your risk and protect your body for years to come. Staying vigilant, consistent and educated about these lifestyle measures empowers you to make meaningful changes that truly matter.