Loss of Appetite
Cancer and its treatment can have effects that lead to changes in eating habits and the desire to eat, including a loss of appetite.
Loss of appetite is called anorexia. People with a very low appetite that lasts more than a few days usually lose weight. Losing weight from not eating enough can often make a person feel weak and have fatigue. This may affect their quality of life and ability to do usual activities. It can also affect how they respond to cancer treatments.
What causes loss of appetite?
People with cancer might have many factors that affect their appetite, most commonly it's the cancer itself and treatment for the cancer.
Cancer itself can cause a loss of appetite for the following reasons.
- If a tumor is in or around parts of the gastrointestinal (GI) tract, it might interfere with the intake of food , may cause trouble swallowing, or make a person feel full without even eating.
- Some tumors release certain types of hormones that affect how the body recognizes that it's hungry.
- Things like pain, stress, depression, dehydration, and nausea that might be related to the cancer itself can reduce a person's appetite.
Surgery and other cancer treatment-related side effects can cause loss of appetite. Some of the side effects that can affect appetite include:
- Changes in taste or smell
- Pain
- Nausea or vomiting
- Constipation or diarrhea
It's important to remember that other non-cancer health problems and medications used to treat non-cancer problems can also cause loss of appetite.
What to look for
A person who has anorexia (poor appetite or no appetite) may eat much less than normal or may not eat at all. This is common with some cancers and some treatments, but it's important to remember that everyone is different. If treatment is the main cause, loss of appetite can be temporary. If there are other factors, it can be longer lasting.
- Little or no interest in food
- Refusing to eat favorite foods
- Weight changes
Some people who lose their appetite may have cachexia. This is a more serious problem that can lead to poor nutrition and a significant loss of weight and muscle mass.
What the patient can do
Eating as well as you can is an important way a person with cancer can help to take care of themselves. It's important to talk to the cancer care team about any expected appetite changes before surgery for cancer, or before other types of treatment are started. Reporting appetite changes early can help limit problems from losing too much weight and having poor nutrition.
Here are some hints that may help if you are having changes in your appetite:
- Eat several small meals or snacks throughout the day, rather than 3 large meals.
- Avoid drinking liquids with meals, or take only small sips of liquids while eating to keep from feeling full early (unless you need liquids to help swallow or for dry mouth). But remember it's important to stay hydrated, so it might be best to drink most of your liquids between meals.
- Make eating more enjoyable by setting the table with pretty dishes, playing your favorite music, watching TV, or eating with someone.
- Be as physically active as you can. Start off slowly, and increase your activity over time as you feel stronger. Sometimes a short walk an hour or so before meals can help you feel hungry.
- Keep high-calorie, high-protein snacks on hand. Try hard-cooked eggs, peanut butter, cheese, ice cream, granola bars, liquid nutritional supplements, puddings, nuts, canned tuna or chicken, or trail mix. (See the table of high-protein foods in Eating Well During Treatment.)
- Review the tips on adding calories and protein to foods and include these in meals and snacks throughout the day.
- Eat your favorite foods any time of the day; for instance, if you like breakfast foods, you can eat them for dinner.
What caregivers can do
- Try giving the patient 6 to 8 small meals and snacks each day.
- Offer starchy foods, such as bread, pasta, or potatoes, with high-protein foods, such as fish, chicken, meats, turkey, eggs, cheeses, milk, tofu, nuts, peanut butter, yogurt, peas, and beans.
- Keep cool drinks and juices within the patient’s reach.
- If the smell of food bothers the patient, serve bland foods cold or at room temperature.
- Create pleasant settings for meals, and eat with the patient.
- Offer fruit smoothies, milkshakes, or liquid meals when the patient doesn’t want to eat.
- Try plastic forks and knives instead of metal if the patient is bothered by bitter or metallic tastes.
- Don’t blame yourself if the patient refuses food or can’t eat.
- Be encouraging, but try not to nag or fight about eating.
- If the patient can’t eat, you might want to offer just your company. Or offer to read to them or give them a massage.
Call the cancer team if the patient
- Feels nauseated and can’t eat at all for a day or more
- Loses 3 pounds or more in a week (or less than a week)
- Has pain when eating
- Doesn’t urinate for an entire day or doesn’t move bowels for 2 days or more
- Doesn’t urinate often, and when they do, it comes out in small amounts, smells strong, or is dark colored
- Vomits for more than 24 hours
- Is unable to drink or keep down liquids
- Has pain that’s not controlled
- Written by
- References
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
Besser J, Grant BL, American Cancer Society. What to Eat During Cancer Treatment. Atlanta, GA: American Cancer Society; 2018.
National Comprehensive Cancer Network (NCCN). Clinical practice guidelines in oncology: Palliative care. Version 2.2019. Accessed at www.nccn.org/professionals/physician_gls/pdf/palliative.pdf on January 21, 2020.
Oncology Nursing Society (ONS). Anorexia. Accessed at https://www.ons.org/pep/anorexia on January 21, 2020.
Rosenzweig MQ. Anorexia/cachexia. In Camp-Sorrell D, Hawkins RA., eds. Clinical Manual for the Oncology Advanced Practice Nurse. 3rd ed. Pittsburgh, PA: Oncology Nursing Society;2014:583-590.
Ward VA. Cancer anorexia-cachexia syndrome. In Brown CG. A Guide to Oncology Symptom Management. 2nd ed. Pittsburgh, PA: Oncology Nursing Society;2015:119-136.
Last Revised: September 14, 2022
American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.
American Cancer Society Emails
Sign up to stay up-to-date with news, valuable information, and ways to get involved with the American Cancer Society.
More Resources
Help us end cancer as we know it, for everyone.
