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Survivorship: During and After Treatment

Managing Eating Problems Caused by Cancer Treatments

Different cancer treatments can cause different kinds of problems that may make it hard to eat or drink. Here are some problems you could have depending on the type of treatment you receive:


After surgery, you will need extra calories and protein for wound healing and recovery. This is when many people have pain and feel tired. They also may be unable to eat a normal diet because of surgery-related side effects. Your body’s ability to use nutrients may also be changed by surgery on any part of the digestive tract (like the mouth, esophagus, stomach, small intestine, pancreas, colon, or rectum).

Be sure to talk to your cancer care team about any problems you’re having so they can help you manage them.

For suggestions on coping with treatment side effects, see Managing Cancer-related Side Effects

For more about information on surgery as a cancer treatment, see Cancer Surgery.

Radiation therapy

The type of side effects radiation causes depends on the area of the body being treated, the size of the area being treated, the type and total dose of radiation, and the number of treatments.

Side effects usually start around the second or third week of treatment and peak about two-thirds of the way through treatment. After radiation ends, most side effects last 3 or 4 weeks, but some may last much longer.

If you’re having trouble eating and have been following a special eating plan for diabetes or another chronic health condition, some of these general tips may not work for you. Talk to your cancer care team about how best to change your eating habits while you’re getting radiation.

Tell your cancer care team about any side effects you have so they can prescribe any needed medicines. For example, there are medicines to control nausea and vomiting and to treat diarrhea.

See How Radiation Therapy Can Affect Different Parts of the Body for more information on its side effects.


Chemotherapy (chemo) side effects depend on what kind of chemo drugs you take and how you take them.

Chemo is often given at an outpatient center. It may take anywhere from a few minutes to many hours. Make sure you eat something beforehand. Most people find that a light meal or snack an hour or so before chemo works best. If you’ll be there several hours, plan ahead and bring a small meal or snack in an insulated bag or cooler. Find out if there’s a refrigerator or microwave you can use.

Some side effects of chemo go away within hours of getting treatment. If side effects last longer, tell your cancer care team. There are things you can do to lessen eating-related side effects. And prompt attention to eating-related side effects can help keep up your weight and energy level and help you feel better.

If you’re having trouble eating and have been following a special eating plan for diabetes or some other chronic health condition, talk to your cancer care team about how best to change your eating habits while getting chemo.

Here are some of the more common problems and tips on how to deal with them. Always tell your cancer care team about any problems you have. There are often things that can be done to treat the problem or keep it from getting worse.

Common eating problems

For more information, see Managing Cancer-related side effects.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as editors and translators with extensive experience in medical writing.

Last Revised: July 15, 2019

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