UNC Health Care

How What You Eat Can Affect Your Risk of Cancer

An oncology dietitian offers advice on designing your diet for health.

It’s no secret that the food we eat has a big impact on our health. Research suggests that certain foods can increase—or decrease—a person’s risk of getting certain diseases, including cancer.

Wondering how to optimize your plate for prevention? Stacy Shappley, an oncology dietitian at UNC REX Healthcare, offers these tips for eating well and reducing your risk of cancer:

  1. Eat a plant-based diet.

“One of the most important recommendations to help reduce a person’s risk for cancer development is for them to follow a plant-based diet,” Shappley says. That doesn’t mean that you have to go completely vegetarian. A plant-based diet puts a bigger emphasis on fruits, vegetables, whole grains, beans, nuts—essentially anything that comes from the ground—with smaller portions of animal products.

Research shows that a plant-based diet has the potential to reduce the risk of many types of cancers, Shappley says, particularly colorectal, breast and gastrointestinal cancers.

The reason? “Part of it comes from the nutrients you get from plant-based foods, including various vitamins, minerals and fiber,” she says. “Plant foods also help promote a healthy weight, and being overweight is one of the leading risk factors in terms of cancer development.”

  1. Embrace variety.

Despite its name, a plant-based diet doesn’t mean eating the same salad for every meal. In fact, the bigger the assortment of food, the more cancer-fighting nutrients your body gets.

“I don’t want people to focus on one specific food. What is more important is the variety of foods they’re eating,” Shappley says. “Cauliflower, for example, can’t provide you with all the different nutrients your body needs. If someone refuses to eat cauliflower, they won’t miss out on those nutrients as long as they’re eating a variety of other plant foods.”

The same goes for other areas of your diet. Not a fan of brown rice? Try quinoa, barley, farro or other whole grains as a replacement.

Another way to add variety into your diet: Experiment in the kitchen.

“Taste and food preference can change as you age, and different cooking methods can affect the flavor and texture of food,” Shappley says. “Have fun in the kitchen and try different cooking methods. You might find that those boiled Brussels sprouts that you hate are delicious when you roast them.”

  1. Limit processed meats and red meat, alcohol and foods that can cause weight gain.

Processed meats—or meat that has been cured, smoked or undergone other processes to transform flavor or improve preservation—are carcinogenic, according to the World Health Organization’s International Agency for Research on Cancer. Once eaten, they can lead cancer-causing compounds to form inside the body.

The agency also says red meat is probably carcinogenic. When cooked at high temperatures, including grilling and charring, carcinogens can form. Frequent consumption of red meat may also increase a person’s risk of cancer, particularly colorectal cancer.

“Because of this, we encourage more lean chicken, other poultry and fish—but we still want to have those in controlled portion sizes as well,” Shappley says. “If you’re going to eat red meat, the American Institute for Cancer Research (AICR) says to limit your intake to no more than 18 ounces per week. In addition, use marinades to precook the meat and lessen the time on the grill. You can also add a layer of foil to the grill while cooking to prevent fat dripping down and causing flames that will char the meat and cook it at higher temperatures. Consider other cooking methods, such as baking and using a slow cooker, too.”

Another cancer contributor: alcohol consumption. “For women, the AICR recommends having no more than one drink per day and for men no more than two,” Shappley says. “But for women who have a greater risk of breast cancer, for example, it’s recommended to have no more than two or three drinks per week.”

Because obesity can also put people at a higher risk for cancer, Shappley recommends limiting high-calorie foods that can contribute to weight gain. This includes sugary drinks, fried foods, fast-food items and other processed junk foods.

“Not only do these foods contribute to obesity, but they also tend to be lacking in important nutrients,” she says. “They have limited amounts of vitamins, minerals, antioxidants—all of those essential cancer-fighting properties that plant-based foods have.”

  1. Don’t do it all at once.

Feeling overwhelmed? Don’t try to overhaul your diet all at once, Shappley says. Instead, start with one manageable change that you can easily maintain. As that first change becomes habit, you can modify your diet further.

“A lot of times clients will want a specific diet or meal plan, but once they finish those meals, they go back to their unhealthy habits,” Shappley says. “Look for opportunities to make maintainable changes that you can implement across a lifetime.”


If you’re ready to change your diet, talk to your doctor about a referral to a dietitian. UNC Wellness Centers and REX Wellness Centers also offer resources for community members.