Chemotherapy and eating problems

Chemotherapy uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. But these drugs may also kill healthy cells that grow and divide quickly, such as cells in the mouth and digestive tract. This can cause eating problems and other side effects, including:

• loss of appetite
• nausea and vomiting
• constipation
• diarrhea
• dry mouth
• sores in the mouth or throat 
• changes in the way food tastes
• trouble swallowing
• feeling full after eating a small amount of food (early satiety)

If you are on chemotherapy, you may have a high risk of infection, including from food (foodborne illness). That is because chemotherapy can reduce the number of your white blood cells, which fight infection. It is important that you and your caregivers learn about how to safely prepare food and how to avoid foods that may cause infection.

Learn more about Chemotherapy to Treat Cancer.

Hormone therapy and eating problems

Hormone therapy may be used to slow or stop cancers that rely on hormones to grow, like breast, ovarian, and prostate cancer. Hormone therapy adds, blocks, or removes these hormones. These drugs can cause weight gain and other side effects, including:

• fluid retention (edema)
• nausea and vomiting
• high blood sugar, also called hyperglycemia
• fatigue

Learn more about Hormone Therapy to Treat Cancer.

Immunotherapy and eating problems

Immunotherapy uses your immune system to fight cancer. The side effects of immunotherapy are different for each person and depend on the type of immunotherapy drug.

Immunotherapy may cause fatigue, which can lead to a poor appetite. Learn more about Cancer Fatigue. 

Common nutrition-related side effects caused by immunotherapy include:

• fever
• nausea and vomiting
• diarrhea

Learn more about Immunotherapy to Treat Cancer.

Radiation therapy and eating problems

Radiation therapy kills cancer cells and healthy cells in the area that is being treated.

Radiation therapy to any part of your digestive system has side effects that cause eating problems. Most of the side effects begin 2 to 3 weeks after radiation therapy begins and go away a few weeks after it is finished. But some side effects can last for months or years after treatment ends. Learn more about Late Effects of Cancer Treatment.

Fatigue, which can lead to a poor appetite, is a common side effect of radiation therapy. Learn more about Cancer Fatigue.

Radiation therapy to the brain or head and neck may cause:

• loss of appetite
• nausea and vomiting
• dry mouth or thick saliva
• sore mouth and gums
• changes in the way food tastes
• trouble swallowing
• pain when swallowing
• being unable to fully open the mouth

Radiation therapy to the chest may cause:

• loss of appetite
• nausea and vomiting
• trouble swallowing
• pain when swallowing
• choking or breathing problems caused by changes in the upper esophagus

Radiation therapy to the abdomen, pelvis, or rectum may cause:

• nausea and vomiting
• bowel blockage
• inflamed colon
• diarrhea
• radiation enteritis

Learn more about Radiation Therapy to Treat Cancer.

Stem cell transplant and eating problems

People who have a stem cell transplant have special nutrition needs. Medications used before or during a stem cell transplant may cause side effects that keep you from eating and digesting food as usual.

Common nutrition-related side effects caused by stem cell transplant include:

• mouth and throat sores
• diarrhea

If you have a stem cell transplant, you have a high risk of infection, including from food (foodborne illness). That is because treatment given before your transplant reduces the number of your white blood cells, which fight infection. It is important that you and your caregivers learn about how to safely prepare food and how to avoid foods that may cause infection.

After a stem cell transplant, you are also at risk of acute or chronic graft-versus-host disease (GVHD). GVHD may affect your digestive tract, skin, or liver and change your ability to eat or absorb nutrients from food.

Learn more about Stem Cell Transplants in Cancer Treatment.

Surgery and eating problems

Surgery is a common part of cancer treatment. Surgery that removes all or part of certain organs can affect your ability to eat and digest food. After any surgery, your body needs extra energy and nutrients to heal wounds, fight infection, and recover. If you are malnourished before surgery, you may have trouble healing.

Common nutrition-related side effects caused by surgery include:

• loss of appetite
• trouble chewing
• trouble swallowing
• feeling full after eating a small amount of food, also known as early satiety

Learn more about Surgery to Treat Cancer.

Targeted therapy and eating problems

Targeted therapy is a type of cancer treatment that targets proteins that control how cancer cells grow, divide, and spread. It may disturb normal function of your digestive system and cause:

• constipation
• diarrhea
• nausea and vomiting
• abdominal pain

Other problems might include taste changes and a dry or sore mouth. Learn more about Targeted Therapy to Treat Cancer.

Ways to manage appetite loss, weight loss, and early satiety

If you have loss of appetite, weight loss, or feel full too quickly, these tips may help:

• Eat foods that are high in protein and calories.
• Eat high-protein foods first in your meal.
• Add extra protein and calories to food.
• Drink most of your fluids between meals, not during meals. Small sips at mealtime are okay.
• Drink milkshakes, smoothies, juices, or soups if you do not feel like eating solid foods.
• Eat foods that smell good.
• Try new foods and new recipes.
• Use a blender to make high-calorie, high-protein drinks.
• Try nutrition supplements, such as Ensure or Boost.
• Aim to eat smaller meals and snacks five to six times a day.
• Eat your largest meal when your appetite is strongest, whether that’s breakfast, lunch, or dinner.
• Make and store small amounts of your favorite foods so they are ready to eat when you are hungry.
• Find a physical activity you enjoy and will stick with to help increase your appetite.

If you continue to struggle to eat and keep up your weight, you and your treatment team can discuss other nutrition support options. These options may include tube feeding or IV nutrition. 

You may also take medicines that increase appetite. Learn more about Weight Changes, Malnutrition, and Cancer.

Ways to manage nausea and vomiting

Nausea is when you feel sick to your stomach, as if you have the urge to throw up. Vomiting is when you throw up. Nausea and vomiting are common side effects of cancer treatments, including chemotherapy and radiation therapy. But there are medicines that often prevent or relieve nausea and vomiting before they start or become a problem.

When you vomit, you may become dehydrated and lose a lot of electrolytes. Electrolytes are minerals, such as potassium, sodium, and calcium that help balance body fluids and support your heart, nerve, and muscle functions. Talk to your dietitian about which drinks can help prevent dehydration and how much you should drink.

Learn more about Nausea and Vomiting and Cancer Treatment.

Ways to manage dry mouth

Dry mouth occurs when you have less saliva than you used to. Having less saliva can make it harder to talk, chew, and swallow food. Dry mouth can also change the way food tastes.

Chemotherapy and radiation therapy to the head or neck can damage the glands that make saliva. Immunotherapy and some medicines can also cause dry mouth.

If you have dry mouth:

• Moisten food with sauce, salsa, gravy, or salad dressing.
• Eat foods that are easy to swallow.
• Try eating foods and drinks that are very sweet or tart, such as lemonade, to help make more saliva.
• Chew sugar-free gum or suck on sugar-free hard candy, ice pops, or ice chips.
• Sip water throughout the day.
• Drink 8 or more cups of water each day.
• Swish and spit with carbonated beverages to remove dry or thick saliva.
• Keep your lips moist with lip balm.
• Floss your teeth every day.
• Ask your doctor about special mouthwashes for dry mouth.
• Do not:

  • use tobacco products 
  • inhale secondhand smoke
  • use electronic cigarettes
  • drink any type of alcohol
  • eat foods that hurt your mouth (such as spicy, sour, salty, hard, or crunchy foods)

Talk with your doctor or dentist about using artificial saliva or a similar product to coat, protect, and moisten your mouth and throat.

Learn about mouth and throat problems caused by cancer treatments.

Ways to manage mouth sores

Cancer treatments can harm fast-growing cells in your mouth. Radiation therapy to the head or neck, chemotherapy, and immunotherapy can cause mouth sores (little cuts or ulcers in your mouth) and tender gums. Dental problems or mouth infections, such as thrush, can also make your mouth sore. Visit a dentist at least 2 weeks before starting immunotherapy, chemotherapy, or radiation therapy to the head and neck.

Your mouth and gums will most likely feel better once cancer treatment ends.

If you have mouth sores:

• Eat soft foods that are easy to chew.
• Cook foods until soft and tender.
• Cut food into small pieces. 
• Use a blender or food processor to make food smooth.
• Suck on ice chips to numb and soothe your mouth.
• Eat foods cold or at room temperature. Hot foods can hurt your mouth.
• Drink with a straw to move liquid past the painful parts of your mouth.
• Use a small spoon to help you take smaller bites, which are easier to chew.
• Check your mouth each day for sores, white patches, or puffy and red areas.
• Rinse your mouth three to four times a day. Mix ¼ teaspoon baking soda, ⅛ teaspoon salt, and 1 cup warm water for a mouth rinse.
• Talk to your doctor about medicine to numb your mouth. This may make eating easier.
• Avoid:

  • citrus fruits, such as oranges, lemons, and limes
  • spicy foods
  • tomatoes and ketchup
  • salty foods
  • raw vegetables
  • sharp and crunchy foods
  • drinks with alcohol
  • mouthwash that contains alcohol
  • tobacco products
  • electronic cigarettes
  • toothpicks or sharp objects

Ways to manage sore throat and trouble swallowing

Chemotherapy and radiation therapy to the head and neck can make the lining of your throat inflamed and sore, a problem called esophagitis. It may feel as if you have a lump in your throat or that your chest or throat is burning. You may also have trouble swallowing. These problems may make it hard to eat and cause weight loss.

Some types of chemotherapy and radiation to the head and neck can harm fast-growing cells, such as those in the lining of your throat. Your risk of sore throat, trouble swallowing, or other throat problems depends on:

• how much radiation you are getting
• if you are getting chemotherapy and radiation therapy at the same time
• whether you use tobacco or drink alcohol during cancer treatment

If you have a sore throat or trouble swallowing:

• Eat soft foods that are easy to chew and swallow.
• Moisten food with gravy, sauces, broth, or yogurt.
• Cook foods until soft and tender.
• Cut food into small pieces.
• Use a blender or food processor to make food smooth.
• Eat five or six small meals every day instead of three large meals.
• Eat foods and drinks that are high in protein and calories.
• Sit upright and bend your head slightly forward when you eat or drink. Stay upright for at least 30 minutes after eating.
• Do not use tobacco or electronic cigarettes.
• Stay away from the foods and drinks that can burn or scratch your throat, such as:

  • hot foods and drinks
  • spicy foods
  • foods and juices that are high in acid, such as citrus, pineapple, and tomatoes
  • sharp or crunchy foods
  • drinks with alcohol
  • carbonated drinks

Talk to your doctor about tube feedings if you cannot eat enough to stay strong.

Ways to manage taste and smell changes

Cancer treatment, dental problems, or the cancer itself can cause changes in your sense of taste or smell. Food may have less taste or certain foods (like meat) may be bitter or taste like metal. Sometimes, foods that used to smell good to you no longer do.

Although there is no way to prevent these problems, there are things you can do to manage them. And often they get better after treatment ends.

Ways to manage a salty taste:

• Try low-sodium or sodium-free seasoning products, like Mrs. Dash.
• Use herbs, spices, and seasonings in place of salt when cooking.
• Pick naturally sweet foods, like fresh or dried fruit.
• Avoid eating out or getting take-out because restaurants often prepare foods with a lot of salt.
• Boil food, as this reduces salty flavors.
• Add a pinch of sugar or honey to foods.

Ways to manage an overly sweet taste:

• Eat more vegetables.
• Add water and ice to dilute sweet juices. Try mixing half juice and half water.
• Eat sour foods, like grapefruit. 
• Add a pinch of salt to food to offset the sweetness.
• Add vinegar or citrus to foods to reduce sweetness.

Ways to manage a loss of taste or “off” taste:

• Choose fresh produce.
• Try foods with fruity, tart, or salty flavors.
• Use marinades on meats to add flavor. Marinate the meat in your refrigerator overnight for more flavor.
• Add vinegars, fresh fruit juices, cheese, salad dressing, and sauces to foods.
• Add fresh or dried herbs, like basil, oregano, thyme, rosemary, mint, or sage.
• Add spices, like onion and garlic powder, paprika, ground turmeric, ground ginger, or curry powder.
• Add condiments, like mayonnaise, relish, ketchup, mustard, or salsa.
• Chew food longer to allow more contact with taste buds.

Ways to manage bitter and metallic tastes:

• Use plastic, silicone, wooden, or bamboo silverware.
• Suck or chew on sugar-free candies, mints, or gum.
• Do not buy prepackaged food in metal containers, such as canned beans. Look for cardboard, glass, or plastic packaging.
• Do not drink from metal containers or use metal silverware.
• Try plant-based protein sources, like tofu, nuts, or beans.
• If red meat tastes metallic, try chicken, turkey, or dairy foods.
• Find nonmeat, high-protein recipes in vegetarian, Chinese, or Indian cookbooks.
• Drink sweet or sour beverages, like cherry, cranberry, pineapple, or grape juice.
• Eat fresh and dried fruits, like mango, peaches, watermelon, dates, or figs.
• Add sweetness to foods with a pinch of sugar, honey, or maple syrup.

Ways to manage smell changes:

• Keep foods covered until ready to eat.
• Drink from cups with lids and drink through a straw.
• Turn a kitchen fan on when cooking, or cook outdoors if smells bother you.
• Avoid strong odors, such as brussels sprouts or fish.
• Make or eat foods that don’t need to be cooked, such as:

  • protein shakes
  • protein bars
  • smoothies
  • cereal with fruit and milk
  • pudding
  • Greek yogurt parfaits
  • sandwiches

Enteral nutrition

Enteral nutrition gives you nutrients in liquid form through a tube that is placed into the stomach or small intestine. There are two types of feeding tubes: 

• A nasogastric tube is inserted through the nose and down the throat into the stomach or small intestine. This is used when nutrition support is needed for only a few weeks.
• A gastrostomy tube is inserted into the stomach, or a jejunostomy tube is inserted into the small intestine through an opening made on the outside of the abdomen. Feeding tubes of this type are usually used for long-term enteral feeding or for people who cannot use a tube in the nose and throat. 

The type of formula used is based on your specific nutritional needs. There are formulas for people with special health conditions, such as diabetes, or with other needs, such as observing religious or cultural norms.

Some people can still eat by mouth when using enteral nutrition. Before doing so, it is important to ask your doctor if it is safe for you.

Parenteral nutrition

Parenteral nutrition is used when you cannot take food by mouth or use a feeding tube. Parenteral feeding does not use the stomach or intestines to digest food. Nutrients are given to you directly into the blood through a catheter inserted into a vein. These nutrients include proteins, fats, vitamins, and minerals.

As with enteral feeding, some people can eat by mouth when using parenteral nutrition. Ask your doctor if it is safe to eat by mouth while receiving parenteral nutrition.

The catheter may be placed into a vein in the chest or in the arm.

A central venous catheter is placed beneath your skin and into a large vein in the upper chest. The catheter is put in place by a surgeon. This type of catheter is used for long-term parenteral feeding.

A central venous catheter is a thin, flexible tube that is inserted into a vein, usually below the right collarbone, and guided into a large vein above the right side of the heart called the superior vena cava.

A peripheral venous catheter is placed into your vein in the arm. A peripheral venous catheter is put in place by trained medical staff. This type of catheter is usually used for short-term parenteral feeding or if you do not have a central venous catheter.

A peripheral venous catheter is a thin, flexible tube that is inserted into a vein. It is usually inserted into the lower part of the arm or the back of the hand.

You will be checked often for infection or bleeding at the place where the catheter enters the body.

You and your family can decide how much nutrition and fluids you will be given at the end of life

People at the end of life often do not feel much hunger at all and may want very little food. Sips of water, ice chips, and mouth care can help with thirst. Food and fluids should not be forced on someone who is at the end of life. Doing so can cause discomfort or choking.

You and your loved ones have the right to make informed decisions. Your religious and cultural preferences may affect your decisions. The health care team and a registered dietitian can explain nutrition needs and the benefits and risks of using tube feeding or IV nutrition at the end of life.

Possible benefits of nutrition support for people expected to live longer than a month include:

• improved quality of life
• less risk of death due to malnutrition
• fewer physical and mental problems

The risks of nutrition support at the end of life include:

• bacteria or toxins in the blood or tissues (known as sepsis) with the use of parenteral nutrition
• accidental breathing in of food or fluid into the lungs (known as aspiration) with the use of enteral nutrition
• sores and breakdown of the skin where the enteral feeding tube is inserted
• diarrhea with the use of enteral and parenteral nutrition
• problems caused by too much fluid in the blood with the use of enteral and parenteral nutrition

Learn more about nutrition support and what to expect during the last days of life.

Causes of weight gain in people with cancer

Fluid retention. Some cancers may cause weight gain due to the size of the tumor or the buildup of fluid. There are different types of fluid buildup, but they all can cause you to gain weight. Learn more at Edema (Swelling) and Cancer Treatment.

Increased appetite. Increased appetite and food cravings that result in weight gain may occur from the cancer itself, cancer treatment, or medicines used with cancer treatment.

Metabolic changes. Hormone therapy may cause weight gain by lowering sex hormones. When you have lower levels of sex hormones, your metabolism slows. Our metabolism is the rate at which we burn energy. A slower metabolism means you burn less energy, which makes it easier to gain weight.

Some hormone therapies and chemotherapy may lead to early menopause in women. Early menopause may decrease your metabolism and cause weight gain. 

Medications. Steroids, which are often given during cancer treatment, increase appetite and make you want to eat more. When we eat more calories than our body burns, we gain weight. If you take steroids, try to eat foods high in fiber and protein at each meal to help you stay full.

Steroids may also cause weight gain by causing your body to hold onto water (fluid retention). If you retain water, you may look and feel swollen. Learn more about fluid retention at Edema (Swelling) and Cancer Treatment.

Decreased activity. Many cancer treatments can cause fatigue and pain, making it hard to be active. Being less active may in turn lead to weight gain. Talk to your doctor about how to manage problems like fatigue or pain to stay as active as possible. Learn more at Cancer Fatigue and Pain and Cancer.

Ways to manage increased appetite and weight gain in people with cancer

Here are some tips to manage increased appetite and slow or stop weight gain. Talk with your doctor or dietitian about these tips and which ones are right for you.

Tips about foods to eat:

• Eat foods high in fiber, such as fruits, vegetables, and whole-grain breads, cereals, and pasta.
• Eat fish, lean meats, such as lean beef, pork trimmed of fat, and poultry (chicken or turkey) without skin.
• Eat plant-based proteins, such as beans, nuts, seeds, and tofu.
• Eat low-fat dairy products, such as 1% and skim.
• Eat foods that you enjoy so you feel satisfied.

Tips about foods to limit:

• Eat less fat.
• Cook with and use less salt to reduce fluid retention.
• Reduce sugary drinks like fruit juices and soda. Try diluting fruit juice with water.
• Limit or do not drink alcohol.

Grocery shopping tips:

• Buy ground meat that is 93% lean or higher.
• Buy leaner cuts of meat, such as “loin,” “sirloin,” or “round.”
• To help control portions, buy food in single-serving containers, such as single-serve yogurts.

Meal prep tips:

• Limit cooking oils. As a general guideline, use 1 teaspoon if cooking for yourself. Use 1 to 2 tablespoons if cooking for more than just yourself.
• Use cooking methods that reduce fat, like baking, broiling, air frying, roasting, and boiling.

Other ways to help with weight gain:

• Plan meals and snacks ahead of time.
• Keep your pantry and refrigerator stocked with healthy snacks.
• Eat only when hungry.
• Find activities you enjoy, if you eat out of boredom.
• Eat more slowly. It takes about 15 minutes for the stomach and brain to know if you are full. Slowing down when you are eating can help you know if you are full or not.
• Eat smaller amounts of food at meals. Use smaller plates.
• Exercise daily.
• Keep a food diary. This can help you see what foods and drinks you eat that help you to manage your weight.

If you have swelling from steroids, try limiting or avoiding foods that are high in sodium, such as:

• breads that have a long shelf life
• sauces
• dressings
• cheese
• deli and canned meats
• olives
• certain frozen foods, such as pizza and frozen dinners
• canned foods (look for low-sodium options)
• table salt
• seasonings with salt

If you don’t want to cut out these foods, look for lower sodium options. You can look at the front of a product to see if it says, “low sodium,” “very low sodium,” or “sodium free.”

Instead of using the saltshaker, use dried or fresh spices like garlic and onion powder or fresh basil and oregano.

Talk with your doctor and dietitian before going on a diet to lose weight. If you eat because of stress, fear, or depression, think about talking with a counselor. Your doctor might also prescribe medicine to help with these feelings. Learn more about Emotions and Cancer.

Causes of malnutrition in cancer

Malnutrition can be caused by the cancer itself, the side effects of cancer treatment, or both.

Cancer and its treatment can cause malnutrition in many ways. They can decrease your appetite, make you feel full quickly, and change your sense of taste and smell. These changes may cause you to eat less. In fact, decreased appetite or appetite loss is a main cause of malnutrition in people with cancer. Cancer may also lead to malnutrition by causing problems with swallowing, digestion, and absorption of your food.

Common treatment side effects that increase the risk of malnutrition are:

• appetite loss
• dry mouth
• mouth sores
• feeling full quickly
• taste changes
• problems swallowing

Cancer and cancer treatments may also cause fatigue, pain, anxiety, distress, and depression, all of which can make eating a challenge, both physically and emotionally. Talk to your doctor and registered dietitian about any of your side effects and concerns. Your team is there to support you and help you manage these challenges.

Problems caused by malnutrition

Malnutrition can cause you to be weak, tired, and not able to fight infection or even finish cancer treatment. Studies show that malnutrition can decrease your quality of life and become life-threatening. 

Screening for malnutrition

Your health care team may use nutrition screenings and assessments to catch eating problems early and measure your risk of malnutrition. Ask your doctor about a nutrition screening before treatment starts and when you should be screened again during treatment.

Ways to prevent malnutrition

Here are tips to prevent malnutrition.

Tips on what to eat:

• Eat foods high in calories and protein.
• Use nutrition supplement drinks, such as Ensure or Boost.

Tips on when to eat:

• Eat small meals spaced throughout the day. Aim for five to six small meals each day.
• Eat every 2 to 3 hours.

Tips on talking with your doctor or dietitian:

• Report loss of appetite and other eating problems to your doctor right away.
• Ask your doctor about a referral to a registered dietitian. A registered dietitian can do a nutrition assessment and provide a nutrition care plan.
• Ask your dietitian about high-calorie and high-protein nutrition supplement drinks.
• Report weight loss of more than 3 to 5 pounds in one week to your doctor.

If you continue to have trouble eating and are losing weight, your doctor or dietitian might suggest tube feeding (enteral nutrition) or IV nutrition (parenteral nutrition). Learn more about tube feeding and IV nutrition at Nutrition During Cancer Treatment.

Inflammation

Inflammation can cause appetite loss, loss of muscle and fat, changes in how the body uses nutrients, decreased eating, and increased metabolism. Lab tests show that certain cancers, such as breast, ovarian, and esophageal cancer, can cause inflammation in the body.

Changes in metabolism

Some cancers can change your metabolism, or how your body uses carbohydrates, protein, and fat from food. Changes may include rapid breakdown of protein and fat stores in the body, causing muscle and fat loss. An increased metabolism also means your body uses more energy. This makes it harder for your body to meet its energy and protein needs, leading to weight loss and possible cachexia.

Not all people with cancer have an increased metabolism. But it is common in those with head and neck, lung, and pancreatic cancers and cancers of the upper digestive tract.

Insulin resistance

People with cancer may have insulin resistance. Normally, after you eat food, insulin tells your cells to allow glucose (sugar) to move from your blood into your cells. But with insulin resistance, the cells no longer respond to insulin. When your cells can’t respond to insulin, glucose can’t enter your cells and it builds up in your blood, causing high blood sugar (a condition called hyperglycemia). And when glucose cannot get into your cells, it is not available to be used by the cells for energy. This can lead to weight loss and possible cachexia.

Changes in hormones

Cancer cachexia may also be caused by a change in hormones, chemical messengers that tell your cells what to do. Two groups of hormones are linked with cancer cachexia: catabolic and anabolic hormones. Catabolic hormones break down tissue, and anabolic hormones build tissue. In cancer cachexia, your body has more working catabolic hormones than anabolic hormones. This imbalance leads to muscle breakdown, making cancer cachexia worse.