Nutrition can become more challenging during chemotherapy. Changes in appetite, nausea, vomiting, diarrhea, constipation, mouth sores, taste changes, fatigue, and difficulty swallowing can make regular meals harder to tolerate. At the same time, the body may require adequate calories, protein, fluids, vitamins, and minerals to maintain strength during treatment.
Chemotherapy can affect healthy cells as well as cancer cells. Cells in the mouth and digestive tract can be particularly sensitive because they naturally grow and divide quickly.
As a result, chemotherapy may cause:
These problems can make it difficult to consume enough food and fluids.
Maintaining adequate nutrition can help preserve muscle mass, support normal body functions, maintain energy, and reduce the risk of malnutrition.
Protein becomes especially important when the body is dealing with cancer and treatment.
Protein supports muscle maintenance and tissue repair. Calories provide energy needed for normal body functions and recovery.
Protein-rich foods can include:
When appetite is poor, calorie-dense foods can make it easier to meet energy needs without eating large portions.
Examples include:
A medical nutrition professional can determine whether additional protein or calorie intake is appropriate.
Large meals can become difficult during chemotherapy, particularly when nausea or early fullness is present.
Instead of three large meals, many people tolerate five or six smaller meals and snacks spread throughout the day.
Small portions can include:
Eating every few hours can provide repeated opportunities to consume calories and protein.
The largest meal can be scheduled during the part of the day when appetite is strongest.
Fluids are important during chemotherapy, particularly when vomiting, diarrhea, fever, or reduced food intake occurs.
Suitable fluids can include:
Some people find it easier to drink small amounts frequently instead of consuming a large glass at once.
When early fullness is a problem, drinking most fluids between meals rather than immediately before or during meals may leave more room for food.
Signs of dehydration can include:
Severe dehydration requires prompt medical attention.
Nausea is a common chemotherapy side effect and can make eating difficult.
Several strategies may help:
Examples of bland foods include:
Anti-nausea medicines prescribed by the oncology team can also play an important role.
If nausea continues despite medication, the treatment team should be informed.
Vomiting can quickly reduce fluid and electrolyte intake.
When vomiting occurs, large meals may be difficult to tolerate. Small sips of fluid can be easier.
Once vomiting settles, foods can gradually be reintroduced.
Suitable choices may include:
Persistent vomiting can cause dehydration and nutritional deficiencies and should be reported to the cancer care team.
Chemotherapy-related diarrhea can lead to fluid and electrolyte losses.
During diarrhea, hydration becomes particularly important.
Foods that may be easier to tolerate include:
Very fatty foods, excessive caffeine, alcohol, and highly spicy foods may worsen symptoms in some people.
High-fiber foods can sometimes aggravate diarrhea, although dietary needs differ according to the cause and severity.
Severe or persistent diarrhea should be reported to the treatment team.
Some chemotherapy medicines, anti-nausea medicines, reduced physical activity, and changes in eating habits can contribute to constipation.
Depending on medical advice, helpful foods may include:
Physical activity, when medically appropriate, may also support regular bowel movements.
Fiber should be increased gradually because sudden increases can cause bloating or discomfort.
If constipation becomes severe or lasts several days, medical advice is important.
Chemotherapy can cause mouth or throat sores that make eating painful.
Soft, moist foods can be easier to tolerate.
Examples include:
Foods that are spicy, acidic, very hot, sharp, crunchy, or heavily seasoned may irritate sores.
Citrus fruits, tomato-based foods, spicy sauces, chips, and rough crackers may become uncomfortable during periods of mouth irritation.
Gentle oral care is also important. Mouth sores, white patches, swelling, or persistent pain should be reported to the cancer care team.
Dry mouth can make chewing and swallowing difficult.
Helpful approaches can include:
Dry foods such as crackers, dry bread, or plain meat may become harder to swallow.
Good oral hygiene is especially important when saliva production is reduced.
Chemotherapy can change how foods taste.
Some foods may develop:
Taste changes can make previously preferred foods unappealing.
Several approaches can help:
Taste changes often vary throughout treatment.
A food that tastes unpleasant during one treatment cycle may become tolerable later.
Strong food odors can trigger nausea or reduce appetite.
Cold or room-temperature foods often produce less smell than hot foods.
Potential choices include:
Kitchen ventilation can also reduce exposure to cooking odors.
When possible, having someone else prepare meals may help when food smells are particularly difficult.
Difficulty swallowing can occur with certain cancers and treatments.
Soft foods may be easier to manage than dry or crunchy foods.
Examples include:
Foods can sometimes be softened with broth, gravy, yogurt, milk, or appropriate sauces.
Difficulty swallowing should be discussed with the medical team because aspiration can become a serious concern.
Some chemotherapy treatments can lower white blood cell counts and increase susceptibility to infection.
Foodborne infections can become more serious when immune defenses are weakened.
Important food-safety practices include:
Food should also be handled carefully by family members and caregivers.
Food safety recommendations can vary according to white blood cell counts and treatment type.
Some cancer care teams may recommend avoiding foods with a higher risk of contamination, such as:
Specific dietary restrictions should come from the oncology team because not every chemotherapy patient has the same infection risk.
Eating before an infusion may help prevent going into treatment on an empty stomach.
A light meal or snack may be appropriate before chemotherapy for many people.
Examples include:
The ideal meal depends on individual tolerance and the chemotherapy regimen.
Heavy, greasy meals may be uncomfortable for people who are prone to nausea.
A chemotherapy day can involve several hours at a treatment center.
A small meal or snacks can be packed in accordance with facility food-safety rules.
Potential choices include:
Fluids can also be packed when permitted.
The treatment center should be informed about dietary restrictions, diabetes, swallowing difficulties, severe nausea, or other conditions affecting food intake.
Unintentional weight loss can become a concern during cancer treatment.
When appetite is low, nutrient-dense foods can provide more calories in smaller portions.
Examples include:
Protein can be added to meals through eggs, dairy products, beans, lentils, tofu, chicken, fish, or other tolerated foods.
Significant weight loss should be reported promptly to the cancer care team.
Liquid and soft foods can provide useful nutrition when solid foods are difficult to tolerate.
Examples include:
A registered dietitian can help determine whether a specialized nutrition supplement is appropriate.
If oral intake becomes inadequate for an extended period, the medical team may consider other forms of nutrition support.
Vitamin and mineral supplements are not automatically necessary during chemotherapy.
Some supplements can interact with cancer medicines or affect treatment in ways that are not desirable.
High-dose antioxidant supplements deserve particular caution because certain chemotherapy treatments rely partly on oxidative damage to cancer cells.
Patients should discuss vitamins, minerals, herbs, protein powders, and other dietary supplements with the oncology team before starting them.
Food-based nutrition is generally preferred unless a healthcare professional recommends supplementation.
Alcohol can worsen certain treatment side effects, including mouth irritation, dehydration, nausea, or interactions with some medicines.
Some cancer treatments may have specific restrictions involving alcohol.
Because chemotherapy regimens differ, alcohol use should be discussed with the oncology team.
Moderate caffeine may be tolerated by some people, while others experience increased nausea, stomach irritation, diarrhea, or sleep problems.
Coffee, tea, energy drinks, and other caffeinated beverages can also contribute to fluid intake patterns.
When diarrhea or dehydration is present, medical advice can help determine suitable beverages.
A common misconception is that completely eliminating sugar will starve cancer cells.
Cancer cells use glucose, but normal cells also require glucose for energy.
Removing all carbohydrates or sugar does not selectively deprive cancer cells of fuel.
During chemotherapy, the more important nutritional concern is maintaining adequate energy and protein intake while following a balanced eating pattern appropriate for individual medical needs.
A restrictive diet can increase the risk of weight loss and malnutrition.
Raw fruits and vegetables are not automatically prohibited during chemotherapy.
The main concern is food safety.
Fresh produce should be washed thoroughly, and damaged or spoiled produce should be discarded.
People with significant immune suppression may receive additional dietary precautions from the oncology team.