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However, treatment side effects can cause you to react differently to food, making healthy eating challenging.

Both cancer and its treatment can produce side effects that may interfere with your ability to eat. These side effects can vary, so it’s important to communicate with your healthcare team as soon as possible if you experience challenges.

Some of these possible side effects are:

  • Loss of appetite (and associated weight loss/malnutrition)
  • Food aversions (changes in how food tastes or smells)
  • Trouble with swallowing
  • A choking sensation while eating
  • Feeling puffy or bloated
  • Dry mouth
  • Sore mouth, tongue or throat
  • Constipation
  • Dehydration

Nausea, diarrhea, fatigue and pain are common side effects of some types of cancer treatments, and can affect your ability to maintain a healthy diet.

Managing Nausea

  • If you have been prescribed anti-nausea medicine, be sure you fully understand your health care team’s instructions for taking that medicine and have a sufficient supply on hand at all times.
  • Talk to your doctor about any other medications you may be taking (including over-the-counter medicines and supplements), as they might contribute to feelings of nausea. Your doctor may recommend changes or advise that you take special precautions.
  • Avoid food with strong odors as well as overly sweet, greasy, fried or highly seasoned food.
  • If possible, stay away from food preparation areas to avoid being around strong odors.
  • Eat small meals or snacks every two to three hours instead of three large meals.
  • Sip water, juices, or other clear liquids throughout the day.
  • Chewing gum or candy (especially tart candy) may help control nausea.

Additional tips to consider:

  • Keep a log of what you eat and drink and how you feel afterwards, as this will allow you to easily determine if certain foods and liquids lead to feelings of nausea.
  • Try to wait at least two hours after eating before lying down.
  • Wear loose-fitting clothes.
  • Rinse your mouth before and after meals.
  • Try slow, deep breathing to calm your stomach.

Managing Diarrhea

  • Over-the-counter medicines such as loperamide (Imodium A-D and others) and prescription drugs are available for diarrhea but should be used only if necessary. If the diarrhea is bad enough that you need medicine, contact a member of your health care team.
  • Choose foods that contain soluble fiber, like beans, oat cereals and flaxseed, and high-pectin foods such as peaches, apples, oranges, bananas and apricots.
  • Avoid foods high in refined sugar and those sweetened with sugar alcohols such as sorbitol and mannitol. It is important to stay hydrated if you experience diarrhea, to replace fluids that are lost. Dehydration can lead to dizziness, mental confusion, muscle spasms and cramps, low blood pressure and weight loss. If dehydration is severe, it can cause damage to the heart, lungs or kidneys.

Here are tips on staying hydrated:

  • Drink plenty of non-caffeinated fluids (e.g. water, herbal tea, juice, broth) throughout the day. Most people need a minimum of 64 ounces (eight 8-ounce glasses), but more fluid is recommended for people experiencing diarrhea. It is best to drink these liquids at room temperature.
  • Avoid drinks with caffeine (e.g. coffee, non-herbal tea, colas, energy drinks).
  • Limit or avoid beverages containing high-fructose corn syrup (e.g., soda, some fruit juices, energy drinks).
  • Ask a member of your health care team or a registered dietitian about using drinks such as Gatorade, which provide electrolytes. Electrolytes are body salts that must stay in balance for cells to work properly.
  • If dehydration becomes severe, your doctor may recommend that a saline solution (a mixture of salt and water) be administered intravenously until your body chemistry returns to normal.

Managing Fatigue

Fatigue (extreme tiredness not helped by sleep) is one of the most common side effects of many cancer treatments. If you are taking a medication, your doctor may lower the dose of the drug, as long as it does not make the treatment less effective. If you are experiencing fatigue, talk to your doctor about whether taking a smaller dose is right for you.

There are a number of other tips for reducing fatigue:

  • Take several short naps or breaks during the day.
  • Take walks or do some light exercise, if possible.
  • Try easier or shorter versions of the activities you enjoy.
  • Ask your family or friends to help you with tasks you find difficult or tiring.

Managing Pain

There are a number of options for pain relief, including prescription and over-the-counter medications. It’s important to talk to a member of your health care team before taking any over-the-counter medication to determine if they are safe and to make sure they will not interfere with your treatments. Many pain medications can lead to constipation, which may make your pain worse. Your doctor can prescribe medications that help to avoid constipation.

Physical therapy, acupuncture and massage may also be of help in managing your pain. Consult with a member of your health care team before beginning any of these activities.

Because of side effects that you may experience (as well as other factors specific to your individual circumstance), it can be challenging to maintain a healthy appetite and take in the daily nutrition you need during your cancer treatment. The following tips may help:

  • To keep from feeling full early, avoid liquids with meals or take only small sips (unless you need liquids to help you swallow). Drink most of your liquids between meals.
  • Eat your favorite foods any time of day. For example, if you like breakfast foods, eat them for dinner.
  • Make your dining experience as pleasant as possible. A few things you can do: turn off the TV, dim the lights, use colorful place settings, play background music.
  • Be as physically active as you can. Sometimes, taking a short walk an hour or so before meals can help you feel hungry.
  • If you are struggling to maintain your appetite, talk to your health care team about whether an appetite-building medication or dietary supplement could be right for you.

Do your best to maintain a nutritious diet during and after cancer treatment. Eating right is important for your health and recovery.

Research shows that whole-foods, plant-based (WFPB) diets are excellent for overall health and wellness. WFPB diets emphasize fresh, whole ingredients and minimize processed foods and animal products.

Approximately two-thirds of what you eat should be plant-based food, such as:

  • Vegetables (fresh or frozen)
  • Beans and legumes (fresh, frozen, dried, canned)
  • Fruit (fresh or frozen)
  • Whole grains
  • Nuts and seed

Approximately one-third of what you eat should be a lean protein, such as:

  • Fish
  • Poultry
  • Plant-based proteins such as tofu, tempeh, and edamame, lentils, chickpeas, peanuts and almonds.

Consult with a member of your health care team before making any changes to your diet. Additionally, a nutritionist or registered dietitian can be a valuable resource, especially one who specializes in working with people undergoing treatment for cancer. Ask a member of your health care team to refer you to resources in your area.

The side effects of cancer treatments can cause weight loss or weight gain. This may affect the way you feel about your appearance and make you self-conscious or anxious. The following are tips to help you cope:

  • Surround yourself with support. Create a network of people who encourage you to share your feelings and who provide non-judgmental support.
  • Ask for help with practical matters. Weight changes can take a physical and mental toll. Having friends and family members help with day-to-day tasks, such as grocery shopping or preparing meals, can help relieve stress.
  • Invest in yourself. Deep-breathing exercises, yoga and mindfulness meditation can help both your mood and physical well-being. Consult with a member of your health care team before beginning any of these activities.
  • Give yourself credit. Focus on the many things you like and respect about yourself, and all of your positive qualities.
  • Join a support group. Support groups provide a chance to meet and interact with people who share similar experiences and understand what you are going through.

As you manage your cancer, it’s important to remember that you are a consumer of health care. The best way to make decisions about health care is to educate yourself about your diagnosis and get to know the members of your health care team, including doctors, nurses, nurse practitioners, physician assistants, dietitians, social workers and patient navigators.

Here are some tips for improving communication with your health care team:

Start a health care journal. Having a health care journal or notebook will allow you to keep all of your health information in one place. You may want to write down the names and contact information of the members of your health care team, as well as any questions for your doctor.

Prepare a list of questions. Before your next medical appointment, write down your questions and concerns. Because your doctor may have limited time, ask your most important questions first and be as specific as possible.

Bring someone with you to your appointments. Even if you have a journal and a prepared list of questions or concerns, it’s always helpful to have support when you go to your appointments. The person you bring may also think of questions to ask your doctor or remember details about your symptoms or treatment that you may have forgotten.

Write down your doctor’s answers. Taking notes will help you remember your doctor’s responses, advice and instructions. You can also ask the person who accompanies you to take notes for you, either in your journal or on a tablet or smartphone.

Record your visit if your doctor allows it. Recording the conversation with your doctor gives you a chance to hear specific information again or share it with family members or friends.

Incorporate other health care professionals into your team. Your medical oncologist is an essential member of your health care team, but there are other health care professionals who can help you manage your diagnosis and treatment:

  • Your primary care physician should be kept updated about your cancer treatment and any test results.
  • Your local pharmacist is a great source of knowledge about the medications you are taking. Have all of your prescriptions filled at the same pharmacy to avoid the possibility of harmful drug interactions.
  • Make sure your oncologist knows of any other medical conditions you have or any pain you are experiencing so that they can consult with your primary care physician or specialist as needed.

Remember, there is no such thing as over-communication.

Q: I read that mouth sores are a side effect of the chemotherapy I’m taking and that they could affect my appetite. How are they treated?

A: If you experience mouth sores (mucositis), a member of your health care team may recommend treatments such as:

  • Coating agents. These medications coat the entire lining of your mouth, forming a film to protect the sores and minimize pain.
  • Topical painkillers. These are medications that can be applied directly to your mouth sores.
  • Over-the-counter treatments. These include rinsing with baking soda or salt water or using “magic mouthwash,” a term given to a solution to treat mouth sores. Magic mouthwash usually contains at least three of these ingredients: an antibiotic, an antihistamine or local anesthetic, an antifungal, a corticosteroid and/or an antacid.

On a related topic, it is very important to maintain good oral health during your cancer treatments. Any mouth and teeth problems that occur can affect your appetite, eating habits and nutritional intake. Talk with your dentist about possibly increasing the frequency of your visits throughout your treatment.

Q: Can you provide healthy eating tips for when I go out to eat?

A: Dining out is a pleasurable and relaxing activity and does not need to disrupt your healthy eating plan. The following are tips that you might find helpful.

  • Ask the server to not bring the restaurant’s usual basket of bread/crackers.
  • Order an appetizer or half-entrée rather than a full entrée.
  • Share a meal with your dining companion.
  • Ask if the dish you order can be prepared or served in a healthier way than may be described on the menu. For example: chicken or fish grilled rather than fried, vegetables steamed without butter, no sauce (or sauce on the side), an extra order of vegetables rather than pasta, fresh fruit rather than french fries.
  • Limit alcohol, as it is high in calories and can weaken your will power.
  • Avoid dessert. If you need something sweet to feel satisfied, ask if you can have fresh fruit, perhaps with a dollop of whipped cream.

Q: What is a treatment summary and why is important?

A: A treatment summary, sometimes called a “shadow chart,” is a document that you create and keep in your possession. Maintaining your own records allows you and your family members to have instant access to the specifics of your cancer diagnosis and treatment. A treatment summary should include:

  • Your name and date of birth
  • Date of diagnosis
  • Prescribed therapy/therapies, including dates started and stopped and dosages when appropriate
  • Dates and types of post-diagnosis testing and the results of these tests
  • Other medications and supplements you are taking
  • Names, affiliations and contact information of all members of your health care team

Talk to your doctor or a member of your health care team about your intention to create a treatment summary, and ask what else they suggest be included. Take your treatment summary with you when you visit any doctor, not just your oncologist.

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Last updated Thursday, May 21, 2020

The information presented in this publication is provided for your general information only. It is not intended as medical advice and should not be relied upon as a substitute for consultations with qualified health professionals who are aware of your specific situation. We encourage you to take information and questions back to your individual health care provider as a way of creating a dialogue and partnership about your cancer and your treatment.

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