Managing Your Diet & Nutrition During Cancer Treatment

When you have cancer, a healthy diet is important to help you stay strong, fight infection, and heal. Yet both cancer and its treatments can affect how your body uses food and make it challenging for you to get the nutrients you need.1

Changes in appetite, eating habits and other related eating side effects can vary, depending on the type of cancer you have and the treatments you’re undergoing. Your eating side effects might also change throughout your journey.

You should always check with your healthcare provider before making any changes to your diet. Here are a few common dietary side effects of cancer treatments and strategies you can discuss with your a healthcare provider to help manage these concerns. 

Common Dietary Side Effects of Cancer Treatments

1. Food aversions

It’s common for radiation and chemotherapy treatments to trigger changes in smell and taste yet “food aversions really tend to come from many different issues related to treatment,” explains Stacy Kennedy, M.P.H., R.D., a certified oncology nutritionist at the Dana-Farber Cancer Institute in Boston, Mass.

You may find that the aroma of meat will turn you off or foods you eat will have no taste, taste metallic or like something foreign, for example. If you already have a decrease in appetite and/or nausea, it’s likely you’ll have food aversions.

“Oftentimes foods, even ones that a patient has loved in the past, end up not being tolerated,” says Alyssa Cohen, a registered dietitian nutritionist who works at a large GI practice in Plantation, Florida. 

If you develop an aversion to foods that are a source of key nutrients, it’s important to find other ways to get those vitamins and minerals into your diet. Since many patients with cancer find it easier to drink their calories than to eat them, try making a smoothie with green vegetables and add in some nut butter, avocado, chia seeds or protein powder. Those mix-ins add calories, vitamins and minerals and healthy fats, according to Cohen. 

Or make soup with pureed vegetables. Try putting the soup in a container with a lid and sip it through a straw, a trick that can help lessen the aroma, Cohen adds.

You can also try to find alternatives to foods that you can’t tolerate. Look for swaps that have the same nutrient profile: for example, thinly sliced turkey instead of a piece of chicken.

It’s also important to make sure you stay hydrated. “When you’re under-hydrated, taste changes are much more pronounced,” Kennedy says.  

2. Nausea

When you’re undergoing cancer treatment, there are different types of nausea. Chemotherapy can cause nausea but you can also have anticipatory nausea. “Thinking about or being on the way to the clinic can trigger nausea,” Kennedy explains. 

To combat nausea, try to have small, frequent meals and eat carbohydrates like mashed potatoes, white Saltine crackers or a piece of toast which can help settle your stomach. “An empty stomach is just as much of a trigger as a full stomach,” Kennedy says. 

High-fat foods can exacerbate GI distress in some people. Fat also slows the rate at which food leaves your stomach, so cutting down on fat means you may be able to tolerate more food. “For someone who is already nauseous or doesn’t have much of an appetite, limiting the fat could make it so that they get more calories overall and more nutrition,” according to Cohen.

Another well-known remedy for nausea2 is ginger. You can cook with ginger root or drink ginger tea, but always talk to your doctor before taking a supplement.

Getting some sodium in your diet may also help whether it’s by using the salt shaker on your meals or sipping broth. “With certain kinds of cancer treatments, patients actually need a bit more salt than normal,” Kennedy says. 

3. Constipation

Certain pain and anti-nausea medications may cause constipation, but being constipated can make nausea worse, according to Kennedy.

Constipation may also occur if your intake of food and drink has fallen, or you avoid fiber-rich foods to ward off diarrhea or vomiting.

Before trying to treat the condition with an over-the-counter remedy, it’s important to first speak to your doctor or a registered dietitian nutritionist to find out the root cause of your constipation. 

Staying hydrated, eating warm foods like oatmeal and moving can all help too. “When we walk, even if it’s very slow, you’re also encouraging movement of your intestinal tract,” Kennedy says. 

4. Diarrhea

Diarrhea is one of the most common side effects of cancer treatments3 and can be triggered by changes in your diet. If your surgery or treatment affects your small intestine, you may develop food intolerances that cause diarrhea. This side effect may be temporary or long-term. 

“One of the biggest challenges with diarrhea during treatment is that your system doesn’t have time to absorb the nutrients from the food that you’re eating,” Kennedy says. 

To help prevent malnutrition which can lead to feeling lethargic, eat and drink slowly which will improve absorption.

Also, avoid foods that are difficult to digest such as those high in fiber, simple sugars like honey, fruit juice concentrates and corn syrup; foods that are spicy4 or those that contain lactose. Eating bland foods that are lower in fiber and fat like bananas, rice, applesauce, and toast may help.

It’s also important to replenish fluids and electrolytes, so each day try to drink 8 to 12 cups of water or clear juices, broth, sports drinks or caffeine-free soft drinks.

Probiotics can help and medication might also be a good idea. “By taking the medication, you can slow that transit time of your GI tract down a notch so you can eat, and actually absorb the nutrients and start to feel better and then over time maybe begin to cut back a bit,” Kennedy says.

5. Mouth dryness, sores, and throat pain

Cancer treatments can lead to dry mouth so staying hydrated is important. Suck on cold foods such as popsicles, or try sour or acidic foods. “Foods that make your mouth pucker can actually stimulate more saliva,” Cohen says.  

If you also have mouth sores or throat pain, which can often be a result of chemotherapy or stem cell transplants, avoid anything spicy, acidic or very hot or cold, Kennedy says. Instead, stick to moist, soft foods like soups, yogurt, stewed chicken, boiled winter squash or mashed potatoes.

6. Weight changes

“Weight gain is something that a lot of people don’t necessarily expect when they’re going through cancer treatments,” Cohen says. Certain medications, such as steroids, can lead to weight gain. Diet changes and fatigue can make you sedentary, which also leads to weight gain. On the other hand, cancer can also increase your body’s metabolic rate, and you may experience weight loss instead.

“If you are looking to lose some weight especially during treatment, you want to do it in a really slow, controlled, safe manner,” Kennedy says.

Make sure you’re getting enough fruits and vegetables and protein, eating small, frequent meals, Follow the Choose MyPlate guidelines: half the plate should consist of vegetables and fruit, one-quarter of protein and one-quarter of starchy vegetables or whole grains. Read labels, cut out added sugars and “try to eat as minimally processed as possible,” Kennedy says. Also, drink plenty of water and move as much as possible.

Regardless of the weight changes you experience, a registered dietitian nutritionist can help you plan healthy meals or suggest a nutritional supplement that will give you the nutrition you need.5

Although you may face eating challenges, continue to try new foods, preparation, and cooking methods and reach out to your healthcare team and your support network for information and advice to make sure you get the nutrition your body needs.



1. Benefits of good nutrition during cancer treatment. American Cancer Society. Accessed November 8, 2017.
2. 4 natural remedies for nausea. Everyday Health. Accessed November 8, 2017.
3. Diarrhea: cancer-related causes and how to cope. Mayo Clinic. Accessed November 8, 2017.
4. Low fiber diet for diarrhea. OncoLink. Accessed November 8, 2017.
5. Academy of Nutrition and Dietetics. Find an Expert. Accessed November 8, 2017.



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