Side Effects from Cancer Treatment That Can Affect Eating

Loss of Appetite
Cancer and treatment can cause changes in your eating habits. When you have a poor appetite, you may eat less than usual or feel full sooner than normal. Not eating enough can cause weight loss, weakness, and fatigue, and can slow the body’s ability to heal. Here are tips to help improve your appetite and maintain your weight:

  • Eat five or six smaller meals per day.
  • Eat your largest meal when you are the hungriest.
  • Eat your high-protein foods first on your plate.
  • Drink beverages that add calories and protein such as milk, sports drinks.
  • Add extra calories at every meal and snack. Try adding cheese, peanut butter, whey protein powder, whole milk, or butter/oil to your meals.
  • If you get full quickly, limit liquids during meals. Drink your beverage 30 minutes after you are done eating.
  • Stock your house with easy to prepare, high calorie, high protein foods:
    • Hard boiled eggs or egg salad
    • Chicken, tuna, or potato salad
    • Cheese or cottage cheese
    • Pudding
    • Yogurt
    • Trail mix, granola bars
    • Nuts and nut butters
    • Bean or creamed soups
    • Soups made with bone broth
    • Casseroles
    • Pasta
    • Protein drinks such as: Ensure Plus, Boost Plus, or Instant Breakfast

Nausea and vomiting can be caused by chemotherapy or from radiation therapy to the stomach, abdomen, or brain. Being nauseated can make it difficult for a person to eat and drink.

Try these ideas for managing nausea and vomiting:

  • Eat smaller amounts of food more often.
  • Eat and drink foods that are room temperature.
  • Choose foods that are bland and easy to digest (crackers, noodles, pretzels).
  • Avoid greasy, spicy, high-fat, or overly-sweet foods.
  • Sip on fluid in between your meals rather that with your meal.
  • Eat sitting up and keep head raised for about an hour after eating.
  • Take anti-nausea medications as prescribed.

Feeling tired is the most common side effect for those diagnosed with cancer. It can be related to the cancer itself or from the treatment. Eating regularly and staying active can help reduce fatigue.

Try these ideas for managing fatigue:

  • Temporarily rely on ready-to-eat foods like deli foods, frozen dinners, or pre-cut fruits/vegetables.
  • Prepare a meal when you feel your best and freeze leftovers in meal-size portions.
  • Stay hydrated.
  • Take a gentle walk if you are able.
  • Accept help with meals from friends and family.

Sore Mouth or Throat
A common side effect of some chemotherapy drugs or radiation therapy to the mouth and throat is an inflammation of the mucus membranes that line the mouth and throat. This is called mucositis and can make it hard to eat and swallow.

Try these ideas for managing a sore mouth or throat:

  • Eat soft foods with extra moisture (gravy, sauces, dressing).
  • Avoid dry, coarse, or rough foods.
  • Avoid alcohol, citrus, caffeine, vinegar, spicy, and acidic foods.
  • Drink plenty of fluids. Try drinking milk to “cool down” your mouth.
  • Rinse your mouth several times a day with a homemade mouthwash (4 cups water, 1 tsp. salt, 1 tsp. baking soda). Do not swallow. Avoid store-bought mouthwashes that contain alcohol or other irritants.
  • Sip on 1 cup of warm water mixed with 1 tbsp. honey.
  • Talk to your health care team about trying products that can numb your mouth and throat.

Taste and Smell Changes
Changes in how foods taste or smell may be caused by radiation or chemotherapy. These changes can affect your desire to eat.

Try these ideas for managing taste and smell changes:

  • Try different seasonings or marinades to mask a strange taste.
  • If foods taste bitter or salty, try adding small amounts of sugar or honey.
  • If foods taste too sweet, try adding lemon juice or a vinegar-based condiment.
  • Try chewing gum or suck on a mint.
  • Eat room-temperature or cold foods. These have less odors.
  • Cover food when cooking; turn on a fan.
  • Brush your teeth and tongue regularly. Rinse your mouth with homemade mouthwash (4 cups water, 1 tsp. salt, 1 tsp. baking soda). Do not swallow. Avoid store-bought mouthwashes that contain alcohol or other irritants.

Dry Mouth
When your mouth gets dry from treatment or medications, it can become difficult to eat and drink.

Try these ideas for managing a dry mouth:

  • Alternate bites and sips at meals.
  • Add broth, gravy, and sauces to meals. Dunk dry foods in liquids.
  • Sip on liquids throughout the day.
  • Chew on celery or carrots.
  • Swish and spit on carbonated water or club soda.
  • Use a humidifier at home to moisten the air.
  • Practice good mouth care.
  • Suck on hard candy, frozen fruit, ice chips.
  • Avoid alcohol and mouthwashes containing alcohol.
  • Try using an artificial saliva product sold in drugstores.

Diarrhea is loose or watery stool that occurs more often than usual. It can be caused by radiation to the abdomen or pelvis, chemotherapy, infection, surgery, medications, or emotions. Diarrhea that continues for several days can cause dehydration, weight loss, weakness, and poor appetite.

Try these ideas for managing diarrhea:

  • Drink plenty of fluids such as water, clear juices, sports drinks, broth. Try to drink at least a cup of liquid after each watery stool.
  • Eat small, frequent amounts of soft, bland foods. Eat foods that have soluble fiber: bananas, white rice, applesauce, or white toast.
  • Avoid foods that are hard to digest like raw vegetables, nuts, seeds, greasy and fried foods, and whole‑wheat bread. Limit dairy foods as well.
  • Eat foods that contain probiotics such as yogurt with live, active cultures.
  • Talk to your doctor about taking anti-diarrhea medicine.

Constipation is when bowels do not move regularly and stools become hard and difficult to pass.  Constipation can be a symptom of cancer itself or caused by medication. It can lead to a poor appetite and weight loss.

Try these ideas for managing constipation:

  • Drink more fluids to keep your digestive system moving, especially water, prune juice, warm juices and lemonade, or decaffeinated tea.
  • Eat foods high in fiber such as whole grains, fresh and cooked vegetables, fresh and dried fruits and foods containing peels, nuts, and seeds.
  • Increase your physical activity as able, such as taking a walk.
  • Talk to your doctor about taking medications for constipation.

Low White Blood Cell Counts and Infection
Cancer and cancer treatment can weaken the immune system which can increase the risk of an infection. White blood cells attack and destroy germs after they enter the body. The risk of infection increases as the number of white blood cells decreases. This condition is called neutropenia. Contact your health care team right away if you think you have an infection.

Try these tips if you have a low white blood cell count:

  • Wash your hands frequently with soap and hot, running water for at least 20 seconds.
  • Do not eat raw or undercooked animal products including meat, eggs, pork, poultry, or fish.
  • Rinse off all fresh fruits and vegetables before eating.
  • Avoid eating foods from salad bars, buffets, or potlucks.
  • Do not drink untested well water or water directly from lakes, rivers, streams, or springs.
  • If using filtered water, change the filter regularly.
  • Keep cutting boards, countertops, and utensils thoroughly cleaned. Change and wash sponges and dish towels often.
  • Properly wrap and refrigerate foods promptly. Refrigerate or freeze leftovers within one hour to limit growth of bacteria.
  • Thaw frozen meat and poultry in the refrigerator, microwave, or cold water. Do not leave out on the counter.
  • Pay attention to food expiration dates. If in doubt, throw it out.