8 Foods to Eat and Avoid for Cancer

Beth Beckett, an oncology dietitian with UnityPoint Health, breaks down the science behind diet and cancer risk. A striking 30-50% of cancers are preventable through lifestyle factors like diet, exercise and weight management. Using research from experts like the American Institute for Cancer Research, Beckett offers clear guidance on foods to eat and avoid to help reduce your risk.

Foods to Eat to Reduce Cancer Risk

When it comes to your plate, the strongest evidence for cancer-fighting foods points to a plant-based diet.

"This doesn't necessarily mean you have to become a vegetarian, although there’s evidence that shows people who don’t eat meat or animal products (studies are still mixed on dairy) have the lowest rates of cancer,” Beckett says.

Instead, the goal is simply to increase your intake of whole foods that are plant-based, like:

• Fruits
• Vegetables
• Beans
• Nuts
• Whole grains

Fruits and veggies are excellent anti-cancer foods, full of natural chemicals called phytochemicals that help protect your cells from the disease forming.

“Berres and citrus fruits, for example, are known for their ellagic acid and Vitamin C, which can help reduce your risk,” Beckett says. “The antioxidant lycopene, which gives tomatoes and watermelon their red color, has been studied for its potential to help as well, particularly for prostate cancer. You can also find beta-carotene in orange vegetables like carrots and sweet potatoes, while the broccoli family contains protective components, too.”

Antioxidants that help fight cancer don't come only from fruits and vegetables. Beckett recommends olive or avocado oil, because they're pressed oils — more natural and not processed with chemicals.

The healthy fats found in nuts can help protect your cells, too. Whole grains, rich in vitamins and fiber, are also beneficial. While the outcomes of fiber-focused research vary, the general thought is a diet high in fiber can help protect against certain cancers, particularly colon cancer.

Another widely researched cancer-fighting diet is the Mediterranean diet.

"It’s about limiting red meat and animal products and filling your plate with more plant foods," Beckett says.

This eating style also focuses on healthy fats like olive oil and includes plenty of fish. She adds that beans, in particular, are another one of the best cancer-fighting foods, because they’re packed with antioxidants.

Foods (and Drinks) to Avoid for Cancer

Just as important as what you eat is what you limit. Beckett highlights some foods and substances to be wary of when it comes to your cancer risk:

• Alcohol: Alcohol is a Group 1 carcinogen and linked to increased cancer risk. There’s no known safe amount.
• Burnt Food: Charred or burnt parts of meat from grilling can contain chemicals that may increase cancer risk.

“Using moist cooking methods more often like braising or slow cooking is recommended,” Beckett says. “At the very least, cutting off any charred parts of grilled meat may help.”

While they’ve grown in popularity over the past decade, air fryers themselves don’t have a cancer warning.

• Processed Meats: Like alcohol and tobacco, they’re classified as Group 1 carcinogens. "There's no known safe amount for processed meats," Beckett says. Examples include hot dogs, bacon, salami and ham.
• Red Meat: Limit red meat to less than 18 ounces per week. The heme iron in red meat can form compounds that damage the gut lining and increase colorectal cancer risk.

"While some people need more heme iron in their diet for anemia, many get more than what’s needed,” Beckett says. “The excess can be converted into nitric compounds that have been linked to cancer.”

Is There a Carcinogen in Soda?

The caramel coloring found in brown sodas is a chemical byproduct known as 4-Methylimidazole (4-MEI). A defined safe amount hasn’t been established, and the amount of 4-MEI varies in each beverage.

This uncertainty is why Beckett says to be mindful of how much soda you consume.

"We don't necessarily have proof that it's harmful, but we know it's not helping," she says.

Avoiding or limiting high-sugar beverages is a common cancer prevention recommendation from organizations like the American Cancer Society.

Does Aspartame Cause Cancer?

It’s not clear whether artificial sweeteners, like aspartame, and certain food dyes, like red 40, cause cancer.

In 2023, the World Health Organization's cancer research agency classified aspartame as "possibly carcinogenic to humans." This decision was based on limited evidence, specifically from studies on a type of liver cancer. More research is needed for red 40, too.

Beckett encourages people to be mindful of their consumption as studies are still ongoing.

Does Sugar Cause Cancer?

While a lot of people worry about sugar, Beckett says its link to cancer still isn’t fully supported by research.

"That's one of the most common questions I get, and the answer is very complicated. While high-sugar foods and beverages aren’t recommended for your overall health, completely avoiding sugar to an extreme level isn’t necessary."

Ultimately, Beckett’s approach to eating foods that reduce your risk of cancer is grounded in balance.

"I like to focus on the positives as much as the negatives," she says. "Increasing the proportion of healthy foods on our plate can help counteract smaller amounts of the things that aren't so good for us."

Food for Cancer Patients

When counseling patients with cancer on nutrition, Beckett tailors her advice to the individual, focusing on what works for them at the time. For example, her approach changes depending on a person’s treatment intent.

"I won’t advise someone with a Stage 4 cancer to go on a strict diet, because we don't have enough evidence on nutrition as a therapy in actually reducing cancer itself," she says.

Ultimately, the most effective approach to diet and cancer risk is a balanced and mindful one. Taking control of your health begins with understanding your food choices. By focusing on increasing the proportion of healthy foods on your plate, you can create a sustainable strategy for long-term wellness that helps you manage risk without unnecessary fear or extreme restrictions.