The body’s response to food

A changing sense of taste

Both chemotherapy and radiation can change your sense of taste. This may be due to changes in both the taste buds and the brain, where taste sensation is perceived. The most common changes are to the sensations of sweetness and bitterness. ⁵

Changes in taste mean favorite recipes and foods may no longer taste good, or at least not taste the same while you are on treatment. You may crave sugary foods or want to sprinkle everything with lemon juice to cut the sweetness. Rinsing your mouth with a salt and baking soda solution (1 teaspoon each of salt and baking soda in a quart of water) before meals can help, according to one cancer survivor at Cancer Survivors Network of the American Cancer Society.

It may help to think, “My sense of taste is new.” As when you try a new dish, expect it to take a couple of attempts to get used to tastes and modify them as needed.

Add cancer-fighting foods to the diet

Research shows many fruits and vegetables, and some other foods, are filled with cancer-fighting compounds that support the idea of food as medicine. These include: ²

• Carotenoids, found in carrots, squash, sweet potatoes, broccoli, kale and more. ³
• Sulforaphanes and other substances found in broccoli, cabbage, cauliflower, and other cruciferous vegetables. ⁴
• Protease inhibitors, found in whole grains, apples, bananas, spinach, and more.

Learn more about cancer-fighting foods at HealingWorksFoundaiton.org. There are many ways to add cancer fighters to your regular diet—replacing a mid-morning cup of coffee with green tea, adding berries to a smoothie or bowl of oatmeal, and roasting vegetables like broccoli and cauliflower or eating them raw for a satisfying, stress-relieving crunch. Plant based foods are especially helpful, according to a large 2024 study that showed just one or two additional servings of plant foods significantly lowered the risk of cancer progression in men with prostate cancer. ⁶

Food safety during treatment

Chemotherapy causes neutropenia, a decrease in white blood cell count that leaves a person more vulnerable to infection. This makes food safety even more important than usual. Keeping hot foods hot, cold foods cold, and cutting boards and utensils germfree is vital when someone in the household has a weakened immune system – even as you make sure you get enough calories for good nutrition. Talk to your cancer specialist or a nutritionist if chemo side effects are affecting your appetite. Memorial Sloan Kettering Cancer Center has a free guide to food safety.

Are dietary changes effective?

Yes. Changing your diet can pay off, as a study of more than 8,000 women from the well-known Nurses’ Health Study shows. Researchers found that women following a diet designed to reduce the risk of developing diabetes reduced the risk of dying from breast cancer by 17 percent compared to women who didn’t follow the diet. ⁷ The diabetes risk-reduction diet meant making the following adjustments:

• Eating more cereal fiber (whole grains).
• Drinking more coffee.
• Eating more nuts and whole fruits.
• Eating more polyunsaturated fats than saturated fats.
• Eating lower glycemic-index foods, meaning foods that have reduced impact on blood sugar, and fewer foods with trans fats.
• Drinking fewer sugar-sweetened beverages and fruit juice.
• Eating less red meat.

Women who followed the diabetes risk-reduction diet were also 33 percent less likely to die from any cause (not just cancer) compared to women who did not follow the diet. This large study shows that diet can be a highly effective intervention for cancer, diabetes, and other conditions.

The World Cancer Research Fund released a major report in 2025 confirming the value of plant-based foods, fiber, healthy weight and physical activity for preventing cancer, specifically colorectal and prostate. Read the report.

Quality matters

The modern grocery store contains many items that are actually harmful to our health. Prime examples are sodas and other sugary drinks, processed meats, and foods that contain no or very few natural substances, such as packaged snacks and fast-food fare. A number of studies have linked ultra-processed foods with cancer risk, and the 2025 World Cancer Research Fund includes them in items to reduce for cancer prevention.

High-quality food typically does cost more than low-quality food. However, it is possible to focus on avoiding the foods most likely to be harmful. The non-profit Environmental Working Group publishes two lists, the Dirty Dozen and the Clean 15, detailing the foods least and most likely to contain pesticides, updated regularly. Get a free, downloadable version of both lists at www.ewg.org.

Sugar and Cancer

The idea that cancer cells feed on sugar comes from the work of Otto Warburg, MD, who nearly 100 years ago studied how cancer cells metabolize sugar. The Warburg Effect, as this is called, leads some patients to feel guilty if they do not give up all sugar containing foods during cancer and treatment.

However, 2024 research from Harvard shows cancer cells use sugar differently than was previously thought. ⁸ They also use other energy sources as fuel, so 2025 research from Stanford recommends against severe sugar restriction during cancer treatment. ⁹ Cutting back is a good idea for people whose diets include significant added sugar, often found in condiments, bottled sauces, yogurts, and other foods we might not expect to be as sugary as desserts. Some tips:

• Look for prepared foods with no added sugar.
• Keep the American Heart Association guidelines for added sugar in mind—just 25 grams per day for women, 36 for men. When you check the label on your favorite yogurt and see 18 grams of sugar, understand that you can still eat it, but sticking with the guidelines will mean avoiding almost all other foods with added sugar that day if you want to stick with the guidelines. ¹⁰ Soda and coffee drinks can also contain a great deal of sugar. Some regular sodas may have more than 40 grams in a single 12-ounce can.

Researchers continue to study the role of sugar in cancer. For now, eating a healthy, balanced diet and adding known cancer fighting foods is likely the best—and most sustainable—approach.

Should you go keto? Or fast?

Many people with cancer are interested in a ketogenic diet.

The Academy of Nutrition and Dietetics explains what this diet involves, who should avoid it, and the pros and cons. You can also learn more from Harvard Health.

Is “keto” necessary if you are serious about fighting cancer? Is fasting linked to survival? Current research shows keto or short erm fasting may help chemotherapy and radiation work more successfully. ¹¹ However, research is still ongoing in this growing field with early clinical evidence. ¹² It is important to note that the heavy emphasis on meat protein intake in ketogenic diet plans is not aligned with cancer prevention guidelines. As an alternative, the Mediterranean diet includes animal protein sparingly and has been extensively studied for its anti-inflammatory properties. Download our free Mediterranean Diet Pocket Guide. The fiber, fruits and whole grains in this diet support healthy microbes that can help your body respond better to treatment and recovery.

Food and emotions

Moving past shame and self-blame

Many patients come to treatment with the idea that they caused their cancer. While it is certainly possible that exposure to smoking, processed meats, and other potential carcinogens played a part, self-blame does not support healing.

The opposite idea is that making the right changes, such as giving up sugar or red meat, will effect a cure. The patient mistakenly feels that they have failed if the cancer does not disappear or go into remission.

In fact, while many cancers are cured, some are not. No dietary intervention has been reproducibly shown to cure cancer. People are not at fault if the malignancy does keep growing. Dr. Jonas’ book How Healing Works offers a deep dive into what it means to create health for mind, body, and spirit.

The comfort of food and drink

Food can be medicine—and it can provide comfort and pleasure. Those are at least as important during the stress of cancer and treatment as when we are feeling healthy. Dr. McManamon agrees: “If you are depressed and craving a comfort food, this might be the time to eat it without guilt. If you are a caregiver, you might fix a favorite food the person with cancer feels like eating, even if it is a ‘bad’ or sugary food.” The nutritional value of food is emotional as well as physical.

Some tips for comfort eating with cancer:

• Try a new comfort food that may be a cancer fighter. Green tea with honey, creamy scrambled tofu, or a side of caramelized roasted sweet potatoes can all be comforting and easy to eat—and are loaded with important nutrients. Also consider adding herbs and spices. These can boost flavor and, in some cases, decrease inflammation.
• Check the lists of cancer-fighting food and come up with your own ideas.

The social side of eating and cooking

More than 40 percent of Americans are now unmarried, and many live alone. Whether or not a caregiver is present, self-care is just as important for people living solo with cancer as for those in families. Nutrition tips include:

• Planning specific meals and snacks. Instead of grabbing whatever is on hand, breakfast might become the time for a smoothie.
• Dr. McManamon advises patients who live alone to make a big pot of soup once a week to have something healthy and easy to prepare on hand.

Patients may have a caregiver who prepares meals for them, or they may be the primary cook for a family group. Cooking can be challenging if the smells of certain foods are nauseating, or fatigue might make it difficult to be present at every family meal. Helpful questions to consider include:

• What can be stocked in the pantry to make it easy for you to eat and for family members to prepare their own meals?
• How can you talk with young children who are distressed that family patterns are disrupted?
• Who can help you shop or cook, if necessary?
• Do you need help cleaning up the kitchen? Can you maintain appropriate food safety and kitchen hygiene for yourself or someone you care for who is immunocompromised?

Believing that what we take in is nourishing us also helps us get used to new foods. Instead of thinking of vegetables as “diet food,” focusing on the nutrients that give them their brilliant colors can help. The nutrition advice to create a “colorful” plate can double for creating a cancer-fighting plate. As you eat to benefit your body, you may find yourself discovering some new favorite foods, experiencing pleasure when you may not have expected it, and creating a new level of health for body, mind, and spirit.

Resources

Author Rebecca Katz has written The Cancer Fighting Kitchen, a cookbook that caregivers and cooks may want to check out. Katz is interviewed in our article “Navigating Nutritional Information as a Cancer Patient and Beyond.”

Cook for Your Life is a nonprofit organization based at Fred Hutchinson Cancer Center in Seattle. It offers recipes, research and much more – just about everything you ever wanted to know about eating and cancer.

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