What To Eat After You’ve Been Diagnosed With Cancer

Originally published October 12, 2017

Last reviewed January 7, 2022

Reading Time: 5 minutes

When you are diagnosed with cancer, you need to develop a practical plan to deal with the disease, including paying close attention to what you eat.

Your body needs enough calories and the right mixture of nutrients to stay strong as you face cancer and its treatment. According to the American Cancer Society, good nutrition is important because cancer, and cancer treatments, can impact how your body uses nutrients and how it tolerates certain foods.

Here are a few things to remember, as you adjust to life after a cancer diagnosis.

Before treatment 

Many nutritionists suggest that you stick with healthful foods, before you begin your treatment. Concentrating on vegetables, fruits, nuts, applesauce, yogurt, brown rice, quinoa and easy-to-prepare essentials is the way to go.

It’s a good idea to make some batches of your favorite meals and freeze them, because you may not have the energy to prepare your meals during the first days or weeks of therapy. Don’t be afraid of asking your friends and family to drop off healthful meals for you during those days, either.

“Many patients ask for an ‘anticancer diet,’ and, unfortunately as of yet, we don’t know what that is,” says Irene Morae Kang, MD, medical oncologist at the USC Norris Comprehensive Cancer Center of Keck Medicine of USC and assistant professor of clinical medicine at the Keck School of Medicine of USC. “We can use common sense and intuition to say eat whole and healthful foods.”

During Treatment

One of the side effects of cancer treatment is that you may have a loss of appetite. On the days when you feel hungry, make sure to load up on high-protein foods, such as lean meats (chicken, turkey and fish), eggs, beans, nuts, seeds, cheese, milk and yogurt. You need to fortify your body and help repair any damage from the treatment.

  • Nutritionists recommend eating at least 2 ½ cups of fruits and vegetables each day. Colorful veggies (dark greens, such as kale and spinach, along with zucchini, cauliflower, and red and yellow peppers) and citrus fruits, such as oranges, lemons and grapefruits, all have plenty of cancer-fighting elements. Be sure to wash them thoroughly, to protect your immune system.
  • Liquids are your friend. Drink plenty of water and fresh-squeezed juice. You need to keep your body hydrated and fortified with vitamins.
  • It’s crucial to eat when you’re hungry. Make breakfast your biggest meal, if that’s when you have the most appetite. If you have no appetite later in the day, resort to liquid meal replacements. If you are finding it difficult to eat bigger meals, go for five or six small ones throughout the day.
  • Healthful snacks can help your body throughout the day. Keep yogurt, cheese and crackers, and organic soups close by. If you’re getting chemotherapy, a snack or small meal, before the treatment, may keep nausea at bay.
  • If you are experiencing side effects, such as fatigue and digestive issues, try food that takes very little or no preparation, to ease your stomach. That means toast, crackers and pretzels; yogurt; sherbet; cream of wheat or oatmeal; boiled potatoes, rice or noodles; skinned chicken that is baked or broiled; and canned peaches or other soft, mild fruits and veggies.

Dealing with side effects

Eating the right foods can help you manage these side effects:

Mouth or throat problems Soft food can help relieve throat sores, throat pain or swallowing issues. Avoid rough, spicy or acidic foods. Eat meals lukewarm, and use a straw for soups or drinks.

Nausea/vomiting It’s best to avoid high-fat, greasy or spicy foods, when you are nauseated. Eat dry foods, such as crackers or toast, every few hours. Sip clear liquids, such as broths, sports drinks and water.

Diarrhea and constipation Drink lots of liquids and cut back on high-fiber foods, such as whole grains and vegetables, to deal with diarrhea. If you’re constipated, slowly add more high-fiber foods to your diet. Staying hydrated can also help.

Taste bud changes Treatment may leave you with a funny taste in your mouth or affect your taste buds. Be open to new foods. Ginger, pomegranates, rosemary, mint and oregano are all helpful to your body’s general health.

Foods to avoid

Cancer patients need to be very careful of consuming food that may be tainted with bacteria. Among the items to avoid at all cost:

  • Unwashed fresh fruit and vegetables, especially leafy vegetables that can hide dirt and other contaminants
  • Raw sprouts, such as alfalfa sprouts
  • Raw or undercooked beef, especially ground beef, or other raw or undercooked meat and poultry
  • Cold hot dogs or deli lunch meat (cold cuts), including dry-cured, uncooked salami. Always cook or reheat these foods, until they are steaming hot.
  • Refrigerated pâté
  • Raw or undercooked shellfish, such as oysters
  • Smoked fish
  • Some types of fish, both raw and cooked, as they may contain high levels of mercury
  • Sushi and sashimi
  • Unpasteurized beverages, such as unpasteurized fruit juices, raw milk, raw yogurt and cider
  • Soft cheeses made from unpasteurized milk, such as blue cheese, Brie, Camembert, feta cheese, goat cheese and queso fresco
  • Undercooked eggs, such as soft-boiled, over easy and poached; raw, unpasteurized eggs; and foods made with raw egg
  • Deli-prepared salads with egg, ham, chicken or seafood

Most nutritionists recommend sticking with a balanced diet of lean proteins, fruits, vegetables, whole grains and low-fat dairy, as well as avoiding sugar, caffeine, salt and alcohol. But every patient is different, and what works for some people may not be good for others.

“Because each patient’s needs are different, there is no one-size-fits-all,” says Kang. “Where protein might be important for one person, to keep their weight up, another person may need to stick to a diet of simple carbs, so as not to upset their stomach. If you are diabetic, it is very important to eat in a way that controls your disease.”

It’s best to consult your physician, for the best way to approach your post-diagnosis dietary needs.

“Ultimately, I encourage my patients to listen to their body and do what works for them,” says Kang. “Cancer is a journey with many unknowns, and we have to choose what feels best.”


balanced diet
cancer care
Dr. Irene Morae Kang
Ramin Zahed
Ramin Zahed is a Los Angeles-based author and journalist.