Nutrition Recommendations During and After Treatment

Approved by the Cancer.Net Editorial Board, 06/2022

When you have cancer, it can be a challenge to eat well and get the nutrition that you need. It is important to find ways to maintain a healthy weight and eat nutritious foods. You also should drink plenty of water.

Sometimes, the side effects of cancer and cancer treatment can cause changes to your appetite and weight. Some treatments can make you want to eat less, causing weight loss. Other cancer treatments can cause weight gain. Small changes in your weight are not a problem. But losing or gaining too much weight can affect your health during cancer and treatment. Good nutrition can help you stay as healthy as possible.

General nutrition recommendations during cancer treatment

Here are some general nutrition recommendations during cancer treatment:

Get essential nutrients. These include protein, carbohydrates, fats, and water. The information below tells you how to get the nutrition you need.

Be as active as you can. For example, take a daily walk. If you sit or sleep too much, you may lose muscle mass and gain body fat, even if you are not gaining weight.

Talk to your health care team about your weight. Be sure to talk regularly with your doctor and others on your cancer care team. Changes to your weight, either losing too much weight or gaining too much weight, can affect your health during treatment. Changes in your weight may also be a sign that you are not getting enough nutrition or the right kind of nutrition. Your health care team can help figure out the reason and what to do next, including talking with a nutrition professional.

How can a registered dietitian or registered dietitian nutritionist help?

If you are having trouble getting the nutrition you need, nutrition counseling may be able to help. Your health care team can recommend a qualified professional. This means a registered dietitian (RD) or a registered dietitian nutritionist (RDN) who has experience working with people with cancer. You can also find a dietitian through the Academy of Nutrition and Dietetics' website.

A dietitian can help you create an eating plan that meets your specific nutritional needs. They may recommend:

  • Vitamins or minerals you need more of

  • Nutrition supplements and snacks

  • Other nutrition support, such as a feeding tube, if needed

There is currently not enough research studying how following specific diets or eating plans during cancer treatment affects quality of life, treatment side effects, or cancer outcomes. Therefore, ASCO does not recommend any specific diet during cancer treatment. More research is needed in this important area.

Treatment side effects and nutrition

Cancer treatment often causes physical side effects that affect your appetite or weight, such as diarrhea, nausea and vomiting, mouth sores, and changes in the way things taste. These may make it difficult to eat and drink. These tips may help.

  • If water does not taste good, get more liquid in foods and other drinks. For example, eat soup or watermelon and drink tea, milk, or milk substitutes. A sports drink is another option. If you are watching your blood sugar, there are sugar-free sports drinks available. Or you can drink water flavored with fruit juice.

  • If food tastes bland, try adding some flavorful herbs and spices. For example, you can try such things as lemon, garlic, cayenne, dill, or rosemary. However, if your mouth is sore, you may need to avoid too much acid, such as lemon or other citrus, or spicy heat, such as cayenne or other hot peppers.

  • Eat several small meals instead of 3 large meals each day. Aim for 6, to make sure the smaller meals add up to give you all the calories you need.

  • If meat is no longer appealing, get protein from other foods. For example, try fish, eggs, cheese, beans, nuts, nut butters, tofu, or high-protein smoothies or shakes.

  • If you have a metallic taste in your mouth, suck on mints or lemon drops, chew gum, or try fresh citrus fruits. Use plastic utensils and cook in nonmetal pots and pans. Also, try brushing your teeth or rinsing your mouth before eating.

  • If you have mouth sores or a gum infection, use a blender or food processor to make the texture of vegetables and meats smooth. For added smoothness and more calories, add butter, mild sauces, gravy, or cream. Try juicing or making smoothies. The extra moisture can help soothe a sore mouth.

It is also important to let your health care team know how you are feeling, as emotional side effects can also play a role. If you are having difficulty eating and drinking because of any side effects, tell your health care team. There are ways they can help, such as prescribing medication that relieve specific side effects.

Should I take dietary supplements?

Before you take any dietary supplements during your cancer treatment, be sure to talk with your cancer care team. This includes taking a multivitamin or other over-the-counter supplements.

Taking low doses of vitamins and minerals could possibly be helpful if you cannot get all the nutrition you need from your food. But it can be harmful to take high doses of any specific supplement based on your cancer care plan. This is true even if another health care provider recommends it.

For your own safety, always talk with your oncologist and cancer care team before taking any supplement. Make sure they know about everything you are taking.

Here are some questions you may want to ask about supplements:

  • What are the benefits of taking this dietary or herbal supplement?

  • What are the possible side effects?

  • Are there risks to taking it?

  • How could this interact with my cancer treatment?

  • How much should I take, and for how long?

  • How much does it cost? Does my insurance cover the cost?

  • Where can I learn more about dietary supplements during cancer?

Read more about dietary and herbal products.

How to prepare food safely during cancer treatment

It is important to be sure your food is safe, especially during cancer treatment. Some treatments weaken the immune system, and this can raise your risk of infections. Food-borne illness happens when harmful bacteria, viruses, or fungi contaminate food and make the person who eats the food sick.

Here are some basic food safety tips.

  • Wash your hands before you handle and prepare food. Also wash them after touching foods such as meat or fish, before you touch other types of food.

  • Rinse vegetables and fruit thoroughly before eating them.

  • Handle and store food safely. For example:

    • Use separate cutting boards for meats and vegetables

    • Store meat and fish on the bottom shelf of the refrigerator

    • Do not thaw food on the counter or under warm running water

    • Refrigerate food right after everyone has been served

  • Eat fully cooked foods. For example, do not eat eggs that are not cooked solid. Avoid raw fish, oysters, and shellfish.

  • Avoid unpasteurized foods. This includes drinks such as unpasteurized cider, raw milk, and fruit juices, and foods such as cheeses made from unpasteurized milk.

  • Avoid buying any food that is past its sell-by or "best by" date. If you need help with the cost of food, during cancer treatment, please talk with your health care team. They may be able to find resources to help your budget.

  • Follow the directions to store your food properly, such as putting foods in the refrigerator after you open them.

Read more about food safety during and after cancer treatment.

Diet and nutrition after cancer treatment

After cancer treatment is complete, most experts recommend a healthy diet that includes plenty of fruits, vegetables, and whole grains. Talk with your cancer care team, including a nutrition professional, about specific nutritional and physical activity recommendations during your post-treatment survivorship.

Doctors do not yet know exactly if or how specific foods and drinks could affect cancer survival rates. But, a healthy diet is important for cancer survivors. There may be a higher risk of other health conditions, such as heart disease, type 2 diabetes, or weak bones, following cancer treatment. Each survivor's needs are unique. In general, many doctors recommend the following steps in a healthy lifestyle after cancer treatment:

  • Eating a nutritious diet, with most foods coming from plants (fruits, vegetables, grains, beans)

  • Staying physically active

  • Quitting smoking

  • Paying attention to changes in your weight

  • Limiting the amount of alcohol you drink (ask your doctor about recommendations)

This information in this article is based on the ASCO recommendations for Exercise, Diet, and Weight Management During Cancer Treatment. Please note that this link takes you to another ASCO website.

Questions to ask the health care team

Consider asking your health care team these questions about the nutrition you need during and after cancer treatment:

  • Do you have any diet or nutrition recommendations I should follow?

  • How can I make sure I'm getting enough nutrition during the treatment? During my recovery?

  • Who should I tell if I have concerns about changes to my weight?

  • What kind of exercise can I do during cancer treatment?

  • Are there any foods I should avoid during cancer treatment?

  • Who can I talk with if I'm interested in taking a dietary supplement during my cancer treatment?

  • How can I prevent foodborne illness?

  • Can you recommend a registered dietitian I can work with?

Related Resources

Spotlight On: Oncology Dietitians

Cancer and Food Anxiety: What to Know and What to Do?


7 Steps for Meal Planning Mastery

Smart Grocery Shopping for a Healthier You

More Information

Fight Bac: The Core Four Practices

National Cancer Institute: Nutrition in Cancer Care

National Cancer Institute: Eating Hints: Before, During, and After Treatment