One of the most important things to do during cancer treatment is to maintain one’s nutritional status or, if possible, improve it. This can be a very challenging time, nutritionally, as each person’s ability to eat during cancer treatment is impacted at some level. We asked Oncology Nutrition Specialists Angela Hummel and Madelyn Wilcox to answer some of the most commonly asked questions about nutrition that come up across the cancer continuum. Here’s what they had to say.

Why is Eating Well Important During Cancer Treatment?

A big reason is to provide the nutrients and energy necessary to support the internal processes of creating, growing, and repairing muscle tissue and bones, organs, and skin. Both cancer and cancer treatments can wreak havoc on the body. Equally important is supporting the critical functions of food digestion and absorption, metabolism regulation, and energy production. This is important when you’re healthy and critical when preparing for, undergoing, and recovering from cancer treatment. Focusing on a varied, nutrient dense, plant-based diet that is loaded with phytochemicals and both macro and micronutrients will help provide your body with the necessary tools for repair and recovery throughout your cancer journey.

What Foods Should I Eat During Treatment?

This is a very common question that most patients wonder about when faced with a cancer diagnosis. It’s a really important question and something you can focus on immediately to help yourself. An oncology dietitian would say, first off, that subscribing to a whole food, plant-based diet is a great starting point. The American Institute for Cancer Research (AICR) offers some great guidance on this with their New American Plate. This healthy eating plate concept recommends that you fill your plate with roughly 2⁄3’s plant-based food and the other 1⁄3 of with a modest 3 ounce serving of poultry, fish, or meat. Any meats should be of the lean varieties like chicken or turkey breast. Red meats and processed meats should be avoided completely. If you are looking to move toward a more vegetarian style diet you should think of the animal protein component as a condiment, to provide flavor and texture to the meal.

One of the main reasons for eating plant-based is access to all of the wonderful nutrients not found elsewhere. The goal is to eat a variety of colors as these contain natural pigments which contain a multitude of rich and varied micronutrients that support good health. Every time you place a new color on your plate, whether it’s a few slices of tomato, some baby carrots, or red onions in your salad, you’ve done your body a great service!

Plant-Based Foods & Fiber

Plant-based eating is also recommended because it provides the body with different types of Fiber. Fiber comes in two forms, soluble in water and insoluble. Some have suggested fiber be listed as an essential nutrient due to its importance to good health. In addition to adding texture to food, fiber can function as a powerful immune booster by feeding specific microorganisms in your gut. Insoluble fiber is like gut lubrication, it helps food move down your GI tract. Soluble fiber, on the other hand, attracts water which tends to slow the passage of food thereby helping with digestion and nutrient absorption. Consuming both in adequate quantities is important.

Fiber is found in a variety of fruits and vegetables as well as oats, brans, nuts, seeds, beans, lentils, and peas. It’s easy to incorporate these foods into a variety of wonderful, healthy plant-based recipes like fruit salads, vegetable stir-fry’s, bean-based chili, red lentil soup, and whole grain bread. Just remember, with extra fiber in your diet, you’ll need to provide yourself with extra hydration.

What Foods Should I Avoid During Treatment?

Many cancer patients also wonder about what foods to avoid or eat less often. Foods to eat less often include highly processed foods especially those that are high in fat and sugar. Fast foods, sugar-sweetened drinks and candy should also be significantly reduced or eliminated completely. Avoiding red meat, processed meat products, and all forms of alcohol is also recommended since they increase your risk of certain types of cancer.

On the more practical side, we know that it’s not always easy to eat during treatment. At times you may not feel like your normal self and it may be challenging to eat due to various side effects. During times like these, and other times when you might crave certain foods, you may want to listen to the messages your body is sending you and then get back on track with your healthier eating as soon as possible. None of us are perfect eaters every meal or every day but our choices do matter and can have a profound impact on our health.

Do People with Cancer Need More Protein?

Most people undergoing any form of cancer treatment will have increased nutrient needs, such as protein, to account for the healing and repair occurring in their body.When people think about protein, their minds often go to muscles and strength but that is only one piece of the protein puzzle. Protein also plays a huge role in building a wide variety of non-muscle body tissues and is also important with things such as hormones and enzymes.

Protein can be found in both plant and animal forms. Some of the plant-based options that are rich in protein include beans, quinoa, tofu, and nuts & seeds. A lot of people think you need animal products such as poultry, seafood, and eggs to meet your daily nutrient and protein needs but that’s not true. Excellent plant-based sources of protein like beans, lentils, peas, quinoa, tofu, nuts & seeds can provide as much or more protein compared to animal sources. Plant-based sources of protein also contain a variety of other micro-nutrients and fiber that contribute to your body’s overall health and healing.

What About Taking Dietary Supplements?

Before considering dietary supplements one should make sure they are currently eating a high quality diet that is full of a variety of plant-based options. This is crucial for ensuring all needed nutrients are consumed, in adequate amounts, day-to-day. Dietary supplements may seem like an appealing option but research does not support the use of supplements for preventing or treating cancer. Furthermore, dietary supplements have not been shown to offer the same benefit as consuming a diet rich in whole food, plant-based sources. One exception would be those individuals that are deficient in a specific vitamin or mineral. This is when supplements may be warranted. If there are certain food groups you can no longer consume, due to side effects from your cancer and/or cancer treatment, talk with your healthcare team and/or book a session with one of the CNC Oncology Dietitians to discuss your concerns further.

Should Sugar and Sugar-Rich Foods Be Avoided?

The concern that sugar can fuel cancer growth continues to create a great deal of anxiety among those with cancer. The truth of the matter is that glucose, aka “sugar”, is responsible for feeding every cell in the human body, cancer cells included. Glucose is the body’s preferred source of energy. Cancer cells, unfortunately, require a great deal of glucose, often leaving less glucose to be utilized by healthy cells such red blood cells, brain cells, and muscle cells. Even if sugar is avoided, the body will continue to make glucose from other macronutrients such as protein and fat. This is why foods containing carbohydrates should not be avoided during treatment or post-treatment, they should just be chosen wisely. Instead of opting for highly processed, refined foods and carbohydrate sources high in added sugars, opt for whole foods or minimally processed carbohydrates such as fruits, vegetables, grains, beans & legumes. Also, try and limit added sugars to 25 grams per day, or less, for women, and 36 grams per day, or less, for men.

What If I Have Additional Nutrition Related Questions?

Cancer Nutrition Care (CNC) was co-founded by a group of Board Certified Specialists in Oncology Nutrition and is here to help you with all your nutrition related questions. Take a look at our list of service offerings and decide what best fits your needs. You can book a basic Q&A session with one of our Oncology Dietitians to discuss what would be best for you. CNC also offers a variety of free nutrition screening tools which you can take advantage of. If you have specific nutrition concerns you should definitely seek assistance from someone on your healthcare team or one of the CNC oncology certified dietitians.

This blog was written and produced by
The Cancer Nutrition Care Editorial Board


Angela Hummel, MS, RDN, CSO
Consulting Oncology Dietitian

Madelyn Wilcox, RD, CSO
Co-Founder, Cancer Nutrition Care


Jeanne Gee, RD, CSO, CDCES
Oncology Dietitian, Cancer Nutrition Care

Lori Bumbaco, MS, RDN, CSO, LDN
Co-Founder, Cancer Nutrition Care

Executive Editor & Producer

Bob Simek
Founder & President, Cancer Nutrition Care