Nutrition Tips for Chemotherapy Patients

Amanda Mondini, RD, LD, Clinical Dietitian

This content was written by Amanda Mondini, RD, LD, one of Thompson Cancer Survival Center’s Clinical Dietitians. 

Overview of Chemotherapy Side Effects

If your doctor has recommended chemotherapy as a treatment for cancer, you are likely processing a whole host of emotions: uncertainty, fear, and stress may be among them. While all of these feelings are valid, know that you have your treatment team to lean on during this difficult time. Chemotherapy, though hard on the body, is an effective tool to combat cancer. There are many different types of chemotherapy, but most have a similar basic mechanism: killing fast-growing cells (such as cancerous cells) in the body. Unfortunately, the mechanism is not targeted enough to spare other fast-growing cells such as hair cells, skin cells, and cells that line the digestive tract. It is for this reason that many people undergoing chemotherapy experience hair loss, rashes, and digestive issues. Other side effects of chemotherapy can include:

  • Nausea/Vomiting
  • Diarrhea
  • Constipation
  • Mouth sores
  • Dry mouth
  • Altered taste
  • Decreased appetite

It will come as no surprise that the above side effects can result in weight loss, which is not favorable while you are undergoing treatment. In fact, the best treatment outcomes are seen when patients are able to maintain their weight throughout the course of treatment. Both cancer and chemotherapy put the body under immense stress. It is not a good idea to drive your body into “starvation mode” during this time.

As a registered dietitian (RD), I have three main goals for you during treatment:

  • Adequate intake of food and fluids
  • Weight maintenance
  • Side effect management

The first two goals are best accomplished by successfully navigating the third goal: side effect management. Below, I am going to answer typical questions that my patients ask about nutrition-related side effects.


Side Effect Management Q & A


Nausea is the feeling of being sick to your stomach. Vomiting occurs when your stomach empties through your mouth.

Q: What should I eat if I am feeling nauseated?

A: Foods well-tolerated are typically bland and include saltine crackers, toast, dry cereal, potatoes, canned fruit, and popsicles. Sometimes, cold or room temperature foods are easier to eat, as they usually have a more mild smell and taste.


Q: What should I avoid eating if I am feeling nauseated?

A: High-fat and high-spice foods should be avoided. Foods with strong odors can also make nausea worse.


TIP: Only consume clear liquids if you are vomiting. Clear liquids include water, Gatorade/Powerade, Jell-O, popsicles, and broth. After the vomiting has stopped, try transitioning to bland foods.


Diarrhea is having loose and/or watery bowel movements at least three times per day. Diarrhea may occur with or without stomach cramping or pain.

Q: Is water the best thing to drink when I am having diarrhea?

A: Water is fine, however, Gatorade/Powerade and Pedialyte are also good options and contain electrolytes (nutrients such as sodium, potassium, and chloride) that help regulate and control the balance of fluids in the body.


Q: What should I avoid eating if I am having diarrhea?

A: High-fat and high-fiber foods should be avoided, as well as strong herbs and spices.


FYI: Diarrhea can cause your body to lose potassium, a nutrient that helps your muscles function properly. Make sure to replenish this nutrient by eating foods with plenty of potassium such as potatoes and bananas


Constipation is when you are having difficulty passing stool. It is typically described as having fewer than three bowel movements per week, but take caution to report any major difference in the frequency of your bowel movements to your healthcare provider.


Q: Are there foods that will help relieve constipation?

A: Yes! Eating certain foods AND drinking plenty of fluids will help promote bowel movements. High-fiber foods such as bran cereal (Raisin Bran), apples with their peels, potatoes with skin, and corn are key.

Mouth sores

Mouth sores are painful ulcers that may be present on the inner lips, gums, roof of mouth, tongue, or throat.


Q: Sometimes my mouth is too sore to eat much food at all. What can I do?

A: Try drinking high-calorie, high protein oral nutrition supplements like Ensure Enlive or  Boost Very High Calorie through a straw. Alternatively, you can make your own high-calorie, high protein shakes and drinks. Click here for recipe ideas!


TIP: Swish and gargle frequently with a salt and baking soda mixture to help prevent and treat mouth sores. Mix one teaspoon of salt and one teaspoon of baking soda in four cups of warm water. You may have to omit the salt if it causes pain.

Dry mouth

Dry mouth is caused by decreased saliva production and can complicate chewing and swallowing. It can also result in decreased taste sensation.


Q: What can I do to make swallowing foods easier?

A: Add sauces and gravies to foods that you are having trouble with. You may also find it helpful to primarily eat moist, soft foods. Examples include casseroles, macaroni & cheese, soups, and pudding.


TIP: Try eating tart foods and drinking tart drinks such as lemonade. This can stimulate saliva production. Don’t try this if you have a sore mouth or throat.

Altered taste

Altered taste creates an unpleasant eating experience; some patients report that everything tastes “too salty” or “too sweet”. Others report that everything “tastes bad” or simply has no taste at all.


Q: I know that I need to eat protein, but all meat tastes bad. What do I do?

]A: Try plant-based protein sources such as nuts and nut butters, beans, cheese, and soy products. You can also increase your protein intake by drinking more oral nutrition supplements.


TIP: If food tastes metallic, try eating with plastic utensils instead of regular silverware.

Decreased appetite

Decreased appetite is when you don’t feel hungry. Your hunger cues may not be working properly or the above side effects may prevent you from feeling like eating.


Q: What are your suggestions for those who have a decreased appetite?

A: I have two very important tips for these folks. First, try your best to get ahead of the other side effects that influence appetite. Take supportive medicines (anti-nausea medicines, appetite stimulants, etc.) as prescribed. Second, eat by the clock. Do not rely on your hunger. Plan to eat a “little something” with calories and protein every 2-3 hours.


TIP: Add extra calories to the foods that you eat. For example, add butter and cheese to grits or a baked potato. Mix fresh or dried fruit and nuts into oatmeal or yogurt.

Hopefully, you will not experience all of these side effects during the course of treatment. Still, as I tell my patients, it is good to arm yourself with knowledge to be prepared.



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