Can What You Eat Lower Your Cancer Risk? 

There is no single food that prevents cancer. But the connection between nutrition and cancer risk is well known. Decades of research show that what you eat has a real impact on your cancer risk.

“There isn’t a specific healthy food or food group proven to prevent cancer,” said Claire McCaughan, RD, LD, a clinical dietitian with Franciscan Health Cancer Center in Indianapolis. “But research has shown that a healthy diet can reduce the risk of cancer developing or returning.”

That last part matters. This is not only advice for people trying to avoid cancer. It applies just as much to those who have already had it.

Key Takeaways: Your Diet & Cancer Risk

• Nearly 20 percent of cancers in the U.S. are linked to excess body fat, poor nutrition and alcohol use.
• A plant-focused diet rich in vegetables, fruits, whole grains and beans is one of the most evidence-based steps you can take.
• Limit processed meats, red meat and alcohol to help reduce your risk.
• These changes matter whether you are trying to prevent cancer or reduce the risk of it returning.

Why Diet And Cancer Are Connected

Understanding how healthy eating and cancer risk are connected is one of the most important steps you can take for your long-term health. According to the National Institutes of Health, of all cancer-related deaths, almost 25–30 percent are due to tobacco, as many as 30–35 percent are linked to diet and about 15–20 percent are due to infections. The remaining percentage is due to radiation, stress, physical activity, environmental pollutants and other factors.

Some cancer risk factors are out of your hands.

“We can’t control some factors, such as aging and genetics,” McCaughan said. “But we can control poor eating habits.”

Diet is linked to several types of cancer, including colorectal, stomach, pancreatic and prostate cancer. Eating plenty of fruits and vegetables may also offer some protection against lung, bladder and oral cancers. And many of the steps that reduce risk for one cancer tend to reduce risk for others as well.

Plant-Based Foods And Cancer Prevention

Experts consistently point to a plant-focused diet as one of the most protective things you can do. Whole, plant-based foods contain phytochemicals, natural compounds that may help prevent cancer.

“A more plant-based diet, one that includes lots of fruits, vegetables and whole grains, is a great way to incorporate phytochemical antioxidants. They help lower inflammation in the body and improve your immune system,” said McCaughan.

Eating a variety of colors helps you take in a wider range of protective nutrients. Red foods like tomatoes, watermelon and guava contain lycopene. And that is linked to reduced prostate cancer risk. Green and white vegetables such as broccoli, brussels sprouts and cauliflower contain lutein, which may help the body eliminate excess estrogen and carcinogens.

When you plan your meals, aim for five or more servings of fruits and vegetables each day, and don’t worry about whether they’re organic.

“There’s no evidence that shows a lower risk of cancer when you eat organic foods,” said McCaughan. “Buy produce that’s accessible and affordable for your family. Just choose to eat more.”

Not ready to go fully plant-based? Try “plant-slant” eating. Keep some of your favorite proteins but build more of your plate around vegetables, whole grains and beans. Small shifts add up. Learn how to make simple swaps to cut your cancer risk.

Foods That Reduce Cancer Risk

Filling your plate with cancer-fighting foods does not require a complete overhaul of the way you eat. McCaughan recommends focusing on two things: what to add and what to pull back on.

Foods to add:

• A colorful variety of vegetables and whole fruits
• Beans, chickpeas and lentils
• Healthy fats found in olive oil, avocados, seeds and nuts
• Water as your primary beverage
• Whole grains such as oatmeal, quinoa and brown rice

Foods to cut back on:

• Processed meats including deli meat, sausage, bacon and hot dogs
• Red meat such as beef, pork and lamb
• Refined and processed foods with added fat or sugar
• Sugar-sweetened drinks such as sodas and sports drinks

“It comes down to moderation and personal choice,” McCaughan said. “If there’s a food you love, enjoy smaller portions once in a while.”

It’s never too late to change your habits for the better to reduce your cancer risk. 

How Alcohol Affects Your Cancer Risk

Unlike diet changes that add more of something good, evidence on cancer prevention suggests that you also eliminate something harmful.

“Alcohol consumption is linked to a variety of cancers,” McCaughan said. “The American Institute for Cancer Research recommends that you avoid it in any form. If you do drink, it’s no more than one drink for women and two drinks for men per day.”

When you drink alcohol, your body breaks it down into a cancer-causing chemical that damages DNA and prevents your body from repairing that damage. The more you drink, the greater your risk. For anyone who has previously had cancer, the guidance is even clearer: it is best not to drink at all.

Diet Changes: Where To Start

You do not need to overhaul your entire diet at once. McCaughan’s advice is simple. “Eat things that provide good nutrition.” Pick one change and build from there. You may swap a sugary drink for water, add a vegetable to dinner or choose whole-grain bread instead of white.

The American Society for Nutrition has recommendations for nutrition for cancer prevention that includes:

• Choose foods and beverages in amounts that help achieve and maintain a healthy weight.
• Limit consumption of processed meats and red meats.
• Eat at least 2.5 cups of fruits and vegetables each day.
• Choose whole grains instead of refined grain products.
• If you drink alcoholic beverages, limit the amount you drink.

A Franciscan Health registered dietitian can help you put together a plan that fits your life, whether you are focused on prevention or how to manage your health after a cancer diagnosis.

Frequently Asked Questions: Cancer Risk & Diet

How can lifestyle changes reduce your cancer risk?

Lifestyle changes can now help decrease the risk of cancer and improve your overall health. According to the American Institute of Cancer Research, maintaining a healthy weight, being physically active, and eating healthy can help reduce your risk of getting cancer. It's all about living a healthy lifestyle in general. Just as with other major diseases, your lifestyle and health play a pivotal role in the likelihood of developing certain ailments. Poor choices can inhibit your overall health, like the addition of cancer-causing habits such as smoking. A healthy lifestyle isn't just about the foods that you eat, but how your diet works with the other parts of your life. Exercise, along with good habits and a healthy diet, can help produce optimal results. 

Does sugar cause cancer?

While it’s not the sugar that causes cancer, it is the excess sugar that is stored as fat that increases a person’s weight, therefore increasing the risk of cancer.