It’s important to eat properly to maintain your health and strength before, during, and after chemotherapy. And because according to the National Cancer Institute (NCI) people with cancer may have different nutritional requirements than healthy people, your usual diet, however balanced, may benefit from some tweaking.

Cancer patients’ nutritional requirements may differ for several reasons: Tumors can change the way the body uses certain nutrients, says the NCI. Furthermore, chemotherapy may change the taste and smell of food and produce side effects such as nausea, vomiting, loss of appetite, diarrhea, and constipation, which make it both difficult to eat and to obtain the necessary nutrients from the foods you do eat.

Food Matters During Cancer

The optimal diet for cancer patients and survivors emphasizes fruits and vegetables, whole grains, legumes, lean protein sources, and foods rich in healthy fats, such as omega-3 fatty acids (commonly found in oily fish and flaxseeds). These foods protect and support your immune system, reduce inflammation, and discourage tumors from creating their own blood supply, thus depriving them of the nutrients they need. They also promote cancer cell death and help your body detoxify. The Dana-Farber Cancer Center recommends filling half your plate with vegetables, one quarter with proteins, and one quarter with whole grains. Your diet should also include small amounts of healthy fats, and always drink plenty of water to prevent dehydration.

If you are suffering from chemotherapy side effects, the following dietary tips can help you feel better, ensure you obtain adequate calories and nutrients, and prevent malnutrition:

  • Clear liquids, such as broth, fruit juices, carbonated beverages that have lost their fizz, and popsicles can help if you have diarrhea, nausea, or vomiting. They are also good choices if you just don’t feel like eating solid foods. Also try smoothies, tomato or vegetable juices, and/or meal replacement drinks.
  • Eat smaller, more frequent meals, and opt for bland, soft foods.
  • If you don’t feel like eating at all, it’s important to consume foods high in calories and protein when you do eat. Soups with cream or legumes, meat, fish, eggs, peanut butter, and sour cream are good choices. Adding powdered milk, dressings, nuts, and seeds to your foods will provide extra calories and protein.
  • Whole grains, such as bran, brown or wild rice, cooked legumes, dried and fresh fruit, and raw or cooked veggies will help if chemotherapy is causing constipation.
  • Some studies suggest that high-quality fish oil, which is generally safe and non-toxic, might help prevent muscle wasting and weight loss in chemotherapy patients. It’s important to consult with your physician before starting supplements while undergoing chemotherapy, as some supplements may impact the effectiveness of treatment.

If possible, meet with a registered dietitian who has experience with cancer patients and can help you—or a loved one—develop an individualized eating plan.

Alison Massey, MS, RD, LDN, CDE, reviewed this article.


"Foods To Help With Side Effects." National Cancer Institute. June 2007. Accessed 17 March 2014. 

"Chemotherapy Side Effects At-A-Glance." National Cancer Institute. June 2007. Accessed 17 March 2014. 

"Overview of Nutrition in Cancer Care." National Cancer Institute. October 2013. Accessed 17 March 2014. 

"Daily Menu for a Person Undergoing Chemotherapy." Dana-Farber Cancer Center. Accessed 17 March 2014. 

"Nutrition Services." Dana-Farber Cancer Center. Accessed 17 March 2014. 

Roxanne Nelson. "Fish Oil Helps Prevent Weight and Muscle Loss in Cancer Patients." Medscape Medical News. 1 March 2011.