Cancer

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Reducing Cancer Risk With a Plant-Based Diet

The Physicians Committee has two cancer-fighting goals. First, we aim to make cancer risk reduction a top priority. Second, and just as important, we want to improve survival after cancer has been diagnosed by offering comprehensive information about the role of dietary factors in keeping people healthy.

More than 2 million people are expected to be diagnosed with cancer in the United States in 2024.1

According to the National Cancer Institute, only up to 10% of cancer cases are linked to genetics; the remaining 90% or more stem from environmental and lifestyle factors and are potentially preventable.2 According to the Global Burden of Diseases, Injuries, and Risk Factors Study 2019, the leading risk factors contributing to global cancer rates were modifiable.3

Risk factors include tobacco and alcohol use, excess body weight, and dietary risks including diets low in fruits, vegetables, legumes, whole grains, and fiber, and high in red meat, processed meat, and sodium. Therefore, factors within our control, like diet and exercise, can play an important role in cancer outcomes.4

There are several ways fiber helps fight cancer of the digestive tract. By definition, fiber cannot be digested. It draws water into the digestive tract. The water and fiber make fecal matter bulkier, so carcinogens are diluted and have less contact with the walls of the intestines. Fiber then moves food quickly through the intestinal tract, helping to eliminate carcinogens as waste.

The more dietary fiber a person consumes, the lower their risk of colorectal cancer, prostate cancer, stomach cancer, and breast cancer.5-11 In the United States, the average daily fiber intake is 10-20 grams per day, but we recommend at least 30-40 grams per day. The best sources of fiber are minimally processed whole grains, beans, peas, lentils, vegetables, and fruits. Foods that are closest to their natural state, unrefined and unpeeled, are highest in fiber.

Low Fat, Plant-Based Diet

Plant-based eaters that consume a wide variety of fruits, vegetables, whole grains, and beans are at the lowest risk for cancer compared with those who eat meat.12 Results from The China Study showed that individuals living in larger cities where the food tends to be richer and higher in animal fat have higher cancer rates than their counterparts living in more rural areas where plant-based foods are the center of the plate.13

The average diet in the United States is about 35.6-36.1% fat according to the Centers for Disease Control and Prevention.14 The recommended daily intake of fat, according to the U.S. Department of Agriculture, is around 30% of one’s calories. Some studies suggest that fat intake should be well below 30% to have an anticancer effect; closer to 15% may be optimal. The World Health Organization and the International Agency for Research on Cancer recommend limiting consumption of processed and red meat for cancer prevention.15 Research links these types of meat with colon, stomach, pancreatic, and prostate cancers.

A study published in 2024 involving overweight women with metastatic breast cancer showed that a whole food, plant-based diet improved health markers.16 After just eight weeks on the diet, women in the intervention group had reduced fasting insulin, reduced insulin resistance, reduced total and LDL cholesterol, an improved hormonal profile, and an average weight loss of 6.6%.

Instead of meat, dairy, and high fat foods, choose plant foods rich in antioxidants, vitamins, minerals, and colors. The more naturally colorful your diet is, the more likely it is to have an abundance of cancer-fighting compounds. The pigments that give fruits and vegetables their bright colors—like beta-carotene in sweet potatoes or lycopene in tomatoes—help you fight cancer.17-19

Alcohol and tobacco have been shown to be carcinogenic and can increase a person’s risk for various cancers such as lung, stomach, liver, and pancreatic.20 Alcohol has been classified as a Group 1 carcinogen by the World Health Organization and it is the most important risk factor for liver cancer.21,22 Chronic, excessive alcohol consumption causes liver cirrhosis, or scarring of the liver, which often progresses to liver cancer. Alcohol is metabolized by the liver cells into acetaldehyde, which is directly toxic to the cells. Chronic alcohol consumption has also been linked to cancers such as colorectal cancer and breast cancer.23

Cancer is one of the leading causes of death worldwide, and there is an urgent need for a new direction in battling this disease. Cancer survivors should strive to eat a plant-based diet rich in fruits, vegetables, whole grains, and fiber. Whole, plant-based foods provide key nutrients that help cancer survivors improve their health, including fiber, B vitamins, magnesium, iron, zinc, and antioxidants.

Higher intakes of fruits and vegetables is associated with reduced risk of mortality among cancer survivors compared with the Western dietary pattern.24 Continuing with a Western dietary pattern post diagnosis can increase the risk of cancer recurrence and mortality. Whole grains have been found to be especially helpful in fighting cancer by providing fiber, vitamins, minerals, and antioxidants. Limit refined grains such as white bread, white pasta, and white flour. Instead, focus on adding in more brown rice, quinoa, whole wheat bread, bulgur, and other whole grains. Soy intake has also been found to be beneficial in reducing breast cancer recurrence.25

What do dairy products, eggs, and meat all have in common? They are all high in saturated fat and cholesterol. Research suggests that for men with prostate cancer eating less saturated fat, especially if substituted for vegetable fat, lowers the risk of mortality.26 A 2021 study found that the addition of half an egg per day was associated with more deaths from heart disease, cancer, and all causes.27 For every 300 milligrams of dietary cholesterol consumed per day, mortality risk increased by up to 24%. Processed meat is even more harmful, and according to the World Health Organization, there is no safe amount of consumption for processed meat.28

Alcohol consumption among cancer survivors is not recommended due to increased risk of recurrence and mortality.24,29 According to the CDC, smoking increases the risk of death, increases the risk for additional cancers, and may increase the risk of cancer recurrence.30

Research shows a diet of fruits, vegetables, whole grains, and legumes can prevent certain types of cancer.

Plant-based foods rich in fiber help remove excess hormones through the intestine and out the door as wastes.

Foods rich in beta-carotene like carrots, winter squash, spinach, and kale improve immunity.

High-fat diets increase estrogen levels linked to cancer growth.

Animal-products like meat and dairy lack fiber and may contain cancer-promoting compounds.

Vegan diets limit saturated fat linked to shorter survival after diagnosis.

“ As a doctor, I want people to know that they already wield some of the most powerful tools to help take control over the risk of cancer: the fork and knife.”

Neal Barnard, MD, President, Physicians Committee

Going Vegan To Keep Cancer In Remission: "Broccoli Rob" Klein

“Basing our diets around plant foods (like vegetables, fruits, whole grains, and beans), which contain fiber and other nutrients, can reduce our risk of cancer.” – World Cancer Research Fund and the American Institute for Cancer Research, Cancer Prevention Recommendations

Health and Nutrition News

Sweet potatoes are high in cancer-preventing beta-carotene.

Health and Nutrition News

Health and Nutrition News

Prevention starts today. Join the 21-Day Vegan Kickstart.