What to Eat After You’ve Been Diagnosed with Cancer

Originally published January 6, 2023

Last updated January 6, 2023

Reading Time: 4 minutes

Woman makes salad with foods that help with cancer treatment and recovery

When you are diagnosed with cancer, knowing what foods to eat can help you deal with the disease and the side effects of treatment.

Cancer and cancer treatments can affect your appetite and how your body uses nutrients from foods. This is why it’s important to give your body enough calories, plus the right mix of nutrients, to help you stay strong throughout treatment.

“Good nutrition is a key part of your cancer treatment and recovery,” says Lisa Statner, MS, RDN, an oncology dietitian at USC Norris Comprehensive Cancer Center, part of Keck Medicine of USC.

Statner shares nutrition tips for people with cancer, including what foods to add to your diet, what foods to avoid and how to prepare an overall nutrition plan, as you adjust to life after a cancer diagnosis.

Set up a nutrition plan before starting cancer treatment

Before you start cancer treatment, it’s important to get a baseline on your diet and nutrition. Statner recommends working with a registered dietitian.

“A registered dietitian can perform a comprehensive nutrition assessment to identify any unique health concerns,” Statner says. “During this assessment, we evaluate your nutritional status, or how your body is absorbing and using nutrients, at the time of your cancer diagnosis. This evaluation also includes looking at your age and any preexisting conditions, like diabetes or malnutrition. These factors help us understand your nutrition needs and make appropriate recommendations.”

Each person’s dietary needs will vary before cancer treatment begins. “In general, a diet rich in colorful fruits and vegetables, complex carbohydrates, lean proteins and healthy fat is appropriate regardless of the type of cancer,” Statner says.

Foods to add to your diet before cancer treatment

Protein: Prior to starting your treatment, Statner recommends adding enough protein in your diet to prevent sarcopenia, or muscle loss, which can occur as a result of cancer and cancer treatment. According to Statner, good sources of protein include:

  • Beans
  • Chicken
  • Cottage cheese
  • Eggs
  • Lentils
  • Seafood
  • Yogurt

Omega-3 fatty acids: “Studies are emerging that show omega-3 fatty acids, especially from fish, flaxseed and walnuts, may help to lessen muscle loss,” Statner says.

Cruciferous vegetables: “Cruciferous vegetables — which include broccoli, cauliflower, bok choy, kale, cabbage and arugula — have long been known to hedge against cancer and cancer recurrence,” Statner says.

Antioxidant-rich fruits and vegetables: She also suggests adding antioxidant-rich, colorful fruits and vegetables to your diet, such as blueberries, blackberries, eggplant, red peppers, papaya, plums and watermelon.

“These antioxidant-rich foods seem to have cancer-fighting properties, as well as anti-inflammatory effects,” Statner says. “‘Eat the rainbow’ is a helpful way to remember to include these foods in your diet.”

During cancer treatment, it’s helpful to think of food as another part of your healing regimen.

Lisa Statner, MS, RDN, an oncology dietitian at USC Norris, part of Keck Medicine

Foods to add to your diet during cancer treatment

Although your nutrition plan may vary based on factors such as the type of cancer treatment you receive and your health at the time of diagnosis, there are key nutrition goals to aim for during cancer treatment.

“Maintaining your weight and understanding your diet tolerance — how much and what types of food you can comfortably eat — are important nutrition goals during treatment for cancer,” Statner says.

“Calorie and protein needs typically increase during treatment, so focusing on nutrient-dense foods is important,” she says. “Try to eat foods that are high in calories and/or high in protein but smaller in volume, such as avocados, peanut or almond butter and honey.”

Other examples of these types of nutrient-rich foods include:

  • Bananas
  • Lentils
  • Oatmeal
  • Olive oil
  • Salmon
  • Sweet potatoes
  • Whole eggs
  • Yogurt (whole milk is preferable)

“Homemade protein smoothies are another good way to double up on nutrients without feeling uncomfortably full,” Statner says.

Mealtime tips for dealing with cancer treatment side effects

Cancer and its treatments can affect your eating and drinking habits in several ways, including loss of appetite, changes in taste or smell, and nausea and vomiting.

“Loss of appetite can occur due to cancer treatments, other medications and even stress,” Statner says. Treatments like radiation therapy may cause a temporary loss of taste, while chemotherapy can make foods taste different.

“Another potential side effect of cancer treatment is a decrease in how much you enjoy food,” she says. “Food is an important part of quality of life, but during cancer treatment, it’s helpful to think of food as another part of your healing regimen.”

Statner also suggests looking out for nausea and vomiting, which can be caused by chemotherapy and radiation therapy. “Make sure you notify your doctor at the first symptom of nausea as an anti-emetic may be appropriate,” Statner says.

The American Cancer Society offers tips for other cancer treatment side effects, such as changes in taste and smell, swallowing issues, and mouth sores and pain.

Foods to avoid while undergoing cancer treatment

Cancer treatments can affect your immune system and your body’s ability to protect itself from infections. It’s important for you to be careful and avoid consuming food that may be tainted with bacteria.

“Good food safety practices are important during cancer treatment. Don’t leave anything to chance,” Statner says.

“Make sure all your fruits and vegetables are washed, even prewashed lettuce and vegetables. Only consume thoroughly cooked meat, poultry, seafood and eggs. I also recommend avoiding all deli meats and uncooked hot dogs, which can expose you to Listeria, a type of bacteria that may be found in those foods.” She also advises staying away from unpasteurized milk products and beverages.

Get the support that’s right for you

Finding a diet that helps you stay strong during your cancer treatment may seem challenging, but your care team can help you get the support you need.

“A registered dietitian can work with you and your family and caregivers to help you understand the side effects of cancer treatment and find solutions to maintain your well-being,” Statner says.

Connect with Our Team

Make an appointment with our registered dietitians to learn about our nutrition therapy services for patients diagnosed with cancer and receiving cancer treatment.
Learn More


Fanny Chavarria
Fanny Chavarria is a writer and editor for Keck Medicine of USC.