Foods to Eat (and Avoid) While Undergoing Chemotherapy


Some foods will worsen nausea and other chemotherapy symptoms, but thankfully, there are plenty of satisfying options that will have either a neutral or even beneficial effect on these.

In the chemotherapy patient’s personal war against cancer, every ounce of control they can wrestle away from the disease is a victory that can contribute to brighter outcomes—especially when it means they can eat foods they enjoy again.

Granted, following the nutritional guidelines for chemotherapy patients listed below doesn’t provide a license to eat anything, but the more you learn, the more tools you will have to reincorporate healthy and satisfying foods into your diet. 

Every cancer/chemotherapy case is unique, and it’s always essential to defer to the primary physician in all treatment-related decisions (including nutrition guidance), but decades of evidence-based investigations have at least sketched a rough outline of important nutritional standards and techniques for chemotherapy patients.

Before we break into those, it’s critical that chemotherapy patients and their loved ones looking to enhance outcomes with nutrition understand the basics of chemotherapy.

How Does Chemotherapy Work?

Chemotherapy entails the use of powerful drugs to target and kill cancer cells.

How this treatment is used (e.g., as a cure, as a pre-surgical measure, or for patient comfort) can vary based on the stage at which the cancer was diagnosed, the patient’s overall condition, and several other factors.

Though rapidly proliferating cancer cells are the primary target of powerful chemotherapy drugs, this treatment also kills off several kinds of healthy, non-cancerous cells.

Hence, chemotherapy patients often experience a vast range of side effects, including, but not limited to:

  • Exhaustion
  • Pain (muscle cramps, headaches, and more)
  • Gum Sores
  • Nausea and Vomiting
  • Diarrhea or Constipation

Chief among the diet-related chemotherapy symptoms that can affect the overall outcome is the issue of wasting, also known as cachexia, due to reduced appetite.

Appetite issues aside, diarrhea, constipation, and nausea can all interfere with the process of replenishing a body that’s desperate for nutrients. 

Thankfully, a particularly important vein of cancer research aimed at counteracting and circumventing many of these issues has delineated many foods that can both help with the symptoms and provide general nutritional support for the chemotherapy patient.

Dietary Influences on Chemotherapy Symptoms

A study by Poznan University of Life Science in Poland examined if and how certain food choices and general eating habits could influence “incidence of selected gastrointestinal symptoms (nausea, vomiting, diarrhea, and constipation)” in chemotherapy patients, finding several connections in the process.

Per the authors, participants (56 females with ovarian cancer) demonstrated an increased incidence of nausea when they consumed oils, and an increased incidence of diarrhea after consuming dairy products, stone fruit (mangoes, peachies, cherries, apricots, etc.), and apples.

Conversely, researchers found that foods rich in fat, protein, carbohydrates, B vitamins, vitamin D, phosphorous, and zinc stifled vomiting, as well as overall caloric intake.

Importantly, they noted that “the difference in energy intake between marginal values of vomiting incidence exceeded 400 kcal (calories).” 

The chemotherapy patient would wisely derive two important lessons from this finding: first, that avoiding the listed foods will decrease chances of nausea, vomiting, and diarrhea, and second, that taking in more nutrient-dense calories will have the same effects.

Now that we’ve got some of the general guidelines down, it’s time to unveil the master list of foods to eat and foods to avoid for chemotherapy patients.

Nutritional Dos and Don’ts for Chemotherapy Patients

We’ve grouped the following foods by function, e.g., which foods you should eat or avoid to overcome specific chemotherapy symptoms.

First, to address the important issue of wasting, it’s important to seek out nutritionally dense protein sources like eggs, protein shakes, skinless poultry, peanut butter, fortified foods, oats, quinoa, and brussel sprouts. 

Eggs especially are extremely nutritious, providing all of the amino acids our bodies don’t produce (aka a complete protein) as well as iron, fat, carotenoids like lutein, and more. 

Many chemotherapy patients develop dysphagia, or difficulty swallowing.

It’s important when transitioning to softer foods to accommodate this symptom that caloric and nutritional density are still at the forefront, which is why experts recommend protein shakes, milkshakes, mashed potatoes (sweet potatoes are even better), hearty soups, and any protein-rich food you could tolerate blended. 

As mentioned, macronutrient (protein, carbs, etc.) and caloric density can help offset nausea, vomiting, and diarrhea, but we didn’t mention these stipulations:

  • Spicy and/or highly acidic foods (peppers, garlic, etc.) can worsen GI distress, despite their nutritional density.
  • Excessively rich, creamy, and/or high-fat dishes can exacerbate GI distress, even without diarrhea.
  • Healthy fruits and vegetables can actually exacerbate diarrhea because of the fiber; soluble fiber (remember, BRAT: bananas, rice, apples, toast) is preferable in this case. 

Conversely, chemo-related constipation is best alleviated with a generous intake of fruits and vegetables, which is why it’s important to dig into the details of each chemotherapy patient’s symptoms. 

Notes on Food Safety

How you eat (and prepare/store food) is arguably as important as what you eat when it comes to nutrition for chemotherapy patients.

Since chemotherapy kills some healthy cells too, the majority of patients are immunocompromised, meaning they’re more susceptible to illness, food-borne or otherwise. 

As such, food safety is paramount.

To minimize the risk of contracting a food-borne illness, the American Cancer Society (via recommends a number of food safety guidelines for chemotherapy patients, such as:

  • Thoroughly washing fresh fruits and vegetables
  • Dedicating one utensil to stirring/tasting and another for eating
  • Avoiding pre-cut produce
  • Avoiding soaps, detergents, bleach, or other products when washing food
  • Keeping all perishable foods fresh in the fridge, especially dairy-based dishes
  • Avoiding cross-contamination whenever possible; using new utensils for new dishes

In other words, maintaining best food-handling practices as a chemotherapy patient can be compared to food safety compliance standards for a restaurant—the idea is to eliminate all opportunities for food-borne illnesses to occur.

Adaptability Is Key 

If we had to choose one takeaway to drive home in this topic area, it would be that there is no cookie-cutter nutritional approach to chemotherapy patients.

Cancer and chemotherapy are chaotic, and can produce a wide range of symptoms that disappear and reappear at random. 

As such, understanding the core concepts (fiber for constipation, soluble fiber for diarrhea, nutrient density for all, etc.) and applying them exactly when they’re needed is more important than memorizing a huge list of “good” and “bad” foods. 

Like all things cancer treatment, nutritional therapy for chemotherapy symptoms is an active and ever-changing effort, but with great promise for improved outcomes.

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