Foods to Avoid While on Chemo

For food lovers, a cancer diagnosis that requires chemotherapy can be difficult to come to terms with. The side effects of chemotherapy on the body are well documented and, unfortunately, they usually are unavoidable.

Depending on the cancer type and chemotherapy drugs used to treat it, the chemicals used to destroy cancer cells can have unintended consequences, causing drastic changes in your eating habits and producing symptoms that make it less desirable to eat. However, choosing the right foods – and knowing which ones to avoid – can help make your cancer treatment journey more enjoyable.

We talk to Juli Johnson, APRN at INTEGRIS Health Cancer Institute to learn what foods are best and what foods to avoid while on chemotherapy.

Why is a chemo diet important?

The body is affected in many ways by cancer and its treatments, such as chemotherapy. Some cancers change how the body circulates blood, others impact the immune system and some types affect the hormone system.

Because of the toll of treatment on the body, what you eat becomes even more important when fighting cancer. Ensuring you have a balance of protein, carbs and healthy fats can help the body heal, fight infection, maintain body weight and provide energy. For example, people with cancer usually need more protein to help with tissue repair and immune system health. Likewise, the body uses carbs as an energy source, and many people fighting cancer with chemotherapy may be more lethargic and lack their typical energy levels.

In cases in which patients undergoing chemotherapy don’t eat a proper diet, malnutrition can lead to weakness and fatigue. Some people may even need to halt treatment if they become too weak.

How does cancer affect your eating?

Chemotherapy is a type of cancer treatment that uses powerful chemicals to destroy and prevent cancer cells from growing. While it can be effective, the chemicals can’t tell the difference between cancer cells and healthy cells, which is why side effects occur.

The healthy cells most commonly damaged by chemo include hair follicles and cells in the nose, mouth, digestive tract and reproductive system.

As it relates to diet and eating, damage to cells in the nose, mouth and digestive tract can alter your ability to both eat and digest food. These side effects then make it more challenging to receive the necessary nutrients you need to fight cancer. You may experience additional issues if you have more than one type of chemo administered, or if the cancer itself produces tumors in any part of the digestive tract – mouth, esophagus, stomach, liver, pancreas, small intestine or large intestine.

Some of the most common food-related chemotherapy side effects include:

• Loss of smell
• Loss of taste
• Constipation
• Nausea
• Vomiting
• Diarrhea
• Fatigue
• Swallowing difficulties
• Mouth sores

A loss of smell or taste makes it less appetizing to eat, as food can become unappealing. Meanwhile, constipation, diarrhea, vomiting, nausea, swallowing difficulties and mouth sores make it less desirable to eat due to physical constraints. 

Most often, these changes cause you to eat less and lose weight. In some cases, you may eat more due to treatment plans that include steroids. Steroids impact your metabolism and increase your hunger.

Foods to avoid

Always take note of what you eat when undergoing chemo. In general, control what you can control by reading labels and making your own food. Here are some examples of foods to avoid.

Fast food and processed foods: Going through the drive thru window or stopping by your favorite restaurant may feel like what your taste buds need, but highly processed foods can be inflammatory and make chemo side effects worse.

Raw meat or seafood: Cancer and chemotherapy burden the immune system, meaning your body can’t fend off pathogens as effectively. Raw meat and seafood come with a risk of foodborne illnesses. This means saying no to raw fish, sushi and other types of raw meat such as tartare, carpaccio or crudo.

Unpasteurized cheeses and dairy products: Raw milk can carry many harmful bacteria, such as E. coli, listeria and salmonella, that can cause food poisoning. Instead, opt for pasteurized milk and dairy products.

Unwashed fruits or vegetables: Fresh produce can contain many bacteria that increase your risk of foodborne illnesses. To help remove pathogens, scrub raw fruits and vegetables before eating. Frozen produce should be soaked in water before eating. Avoid produce that is hard to scrub, such as blueberries, blackberries, raspberries or strawberries. If you’re receiving intense chemo for a blood cancer like leukemia or lymphoma, you may be advised to avoid raw produce altogether regardless of if it’s washed.

Raw nuts: Raw nuts can fall on the ground or may be thrown to the ground during harvesting, which poses a health risk for chemo patients. Choose roasted nuts when you’re at the grocery store.

Food at buffets or salad bars: There is a higher risk of developing a foodborne illness due to improper food handling or leaving foods at room temperature for too long. At home, don’t eat any food that has been sitting out at room temperature for more than two hours.

Spicy or acidic foods: Mouth ulcers are one side effect of chemotherapy, and eating spicy foods or acidic foods can aggravate mouth sores – capsaicin found in spicy foods and acid in fruits and vegetables act as irritants. Hard foods or foods with sharp edges, such as chips or crackers, can also aggravate mouth sores.

Frozen foods: Some chemo drugs, such as oxaliplatin to treat colon, pancreatic, stomach and esophageal cancers, damage nerves that lead to cold sensitivity. Usually, patients with cold sensitivity become uncomfortable or even experience pain when eating ice cream, smoothies and other cold foods and drinks.

Foods to avoid for chemo-specific symptoms

Symptoms of chemo can vary, but here are some specific tips on foods to avoid if you experience any of these side effects.

For nausea: 

• Avoid foods that are greasy, fried or are heavily spiced
• Avoid foods with strong odors

For constipation:

• Reduce caffeine intake

For dry mouth:

• Avoid spicy or acidic foods
• Avoid foods with sharp edges
• Avoid alcohol

For diarrhea: 

• Avoid foods high in lactose (milk, ice cream and puddings)
• Avoid fried, greasy or spicy foods
• Avoid raw vegetables with skins or seeds

For swallowing difficulties:

• Avoid spicy or acidic foods
• Avoid foods with sharp edges
• Avoid hot foods

For changes in smell/taste:

• Avoid red meats (some people find they taste metallic) 

What are the best foods to eat while on chemotherapy?

In general, eat bland foods before treatment. Examples include fruit, toast, cereal and milk, crackers or chicken soup.

In the immediate days of receiving chemo, focus on eating small meals (five to six per day) and bland foods. Stay hydrated by drinking fluids and eating foods with a high water content – watermelon, cucumber, tomatoes, berries, celery, apples, carrots or grapefruit.

“I would encourage patients to always look for nutrient dense foods versus foods that lack quality nutritional value. With decreased appetites, this can help ensure they are getting good nutrition versus eating foods that are nutrient deficient. Look for room temperature foods when your taste is an issue. They tend to have less odor. Also, foods like peanut butter, avocados, hard boiled eggs, full fat yogurt, cheese and crackers can be good options for nutrient dense small snacks,” says Johnson.

Here is a general list of foods that are easy on the stomach:

• Avocado
• Baked skinless chicken or turkey
• Eggs
• Broiled fish
• Plain pasta noodles
• Peanut butter
• Baked potato (without skin)
• Pretzels
• Refined cereals
• Saltine crackers
• White bread
• White rice

Once you settle into a routine, you’ll want to map out a plan to eat healthier foods in between treatments to keep you energized. Try selecting foods from the following three groups.

Plant-based proteins: Beans, legumes, nuts and seeds combine protein with vitamins and minerals that can provide nourishment during chemo treatment. They are often a better alternative than animal-based proteins that tend to be high in saturated fat.

Healthy fats: Speaking of fats, opt for monounsaturated and polyunsaturated fats when choosing oils for cooking. Examples include olive oil or avocado oil.

Healthy carbs: Typically, whole grains are good options for people going through chemo treatments. This means opting for whole wheat pasta instead of regular pasta, brown rice instead of white rice or whole wheat bread instead of white bread. There are instances, though, where carbs high in fiber can lead to constipation. Talk to a doctor to see what works best for you.

Ultimately, each cancer is specific to the individual, and side effects will vary. Therefore, there isn’t a one-size-fits-all list of foods to eat or avoid. What works for one person going through chemotherapy may not work for you.

Your oncologist can help answer any questions you have on dietary needs while receiving chemo. If necessary, they can refer you to a nutritionist or registered dietician to help keep you on track.