By: Mike Harlos MD, CCFP(PC), FCFP

What is anorexia (lack of appetite)?

Lack of appetite is the feeling that you are not hungry. Most people experience a lack of appetite from time to time. For example, people recovering from the flu often do not feel like eating until they begin to recover.

Anorexia is a medical term used to describe a complete lack of appetite and loss of interest in food that persists over an extended period of time. Anorexia is different from occasional loss of appetite because it lasts for a much longer period.

People with anorexia have no desire to eat, even if they haven’t eaten for hours or days. Some of the things that can affect a person’s appetite include illness, medications, medical treatments, pain, constipation or bowel obstruction, sores in the mouth, and feelings of anxiety and depression.

Patients with advanced illness, particularly near the end of their lives, frequently develop anorexia. This is not the same as the eating disorder known as anorexia nervosa.

What is cachexia (loss of weight)?

Weight loss in healthy people usually happens through a combination of decreasing the amount of calories eaten and increasing physical activity. The weight loss that happens in advanced illness is much different.

Weight loss that people with advanced illness experience is not due simply to the fact that they are not eating much. Instead, abnormalities occur in the way the body is able to use food. It is these abnormalities that result in weight loss. Cachexia is a medical term to describe the weight loss and muscle wasting that occurs when the body is unable to process nutrients from food. Cachexia is pronounced ka-KEK-see-a.

This means that even if food could be taken in, the body would not able to use it to build muscle and fat tissue that would result in maintaining or gaining weight.

People with anorexia and cachexia often experience extreme feelings of fatigue and may feel persistent nausea.

Causes of anorexia and cachexia

The exact causes of lack of appetite in advanced illness are not completely understood. Factors related to the illness itself, a person’s immune system, and altered chemical reactions in the body are all involved. Generally, there are two main reasons for weight loss. The health care team’s approach will depend on which one of these two reasons is responsible for the lack of appetite and weight loss.

Inability to swallow or digest food

 This is usually due to:

  • some type of blockage, such as an obstruction in the throat, esophagus (the passage from the mouth to the stomach), stomach, or intestines;
  • decreased alertness, making swallowing impossible or unsafe;
  • failure of the digestive system to absorb food, such as in severe diarrhea.

In these situations, it is possible that the body can use nutrients if they can be taken in. It may be reasonable to consider feeding tubes or total parenteral nutrition as possible treatment options, depending on the overall circumstances.

Inability of the body to process the nutrients in food

This is the most common cause of severe weight loss (cachexia) in advanced illnesses such as cancer, and is almost always accompanied by a lack of appetite (anorexia). In the presence of serious illness, the body obtains energy by breaking down its own muscle and fat rather than making use of the nutrients in food. Even if food is swallowed and digested, the body cannot make use of the nutrients.

In these situations, the body is unable to use nutrients, even if they could be taken in. In such cases, alternative feeding methods are not likely to help stop the weight loss that is occurring.

Sorting out symptoms

To determine possible causes of the lack of appetite or loss of weight, the health care team will often ask questions, complete a physical examination, or arrange for further testing.

Questions from the heath care team

Your health care team may ask some of the following questions to better understand the extent of your symptoms and possible causes:

  • How troublesome is the lack of appetite?
    • Mild, moderate, or severe?
    • Rate the lack of appetite on a scale from 0 to 10. Zero means the person’s appetite is as good as it can be, while a 10 means no appetite at all.
  • When did the lack of appetite start?
  • How long does it last?
    • Is the poor appetite always there, or does it come and go?
  • What makes it better?
    • Certain types of food or drink?
    • Eating or drinking in a particular location?
    • Anything else?
  • What makes it worse?
    • Certain types of food or drink?
    • Cooking odours?
    • Anything else?
  • Has weight loss been experienced?
    • How much weight has been lost?
    • Over what period of time?
  • Is there nausea or vomiting associated with the lack of appetite, or is it simply a case of not feeling like eating?
  • How have the bowels been working?
    • Is there constipation, bloating, or diarrhea?
  • Is there any pain or discomfort in the abdomen?
  • How much concern does the patient have about not feeling hungry? Sometimes family and friends are more concerned about lack of appetite than the person who is experiencing it.

Physical examination

Since lack of appetite and loss of weight are symptoms that can be caused by many different problems, the health care provider will usually complete a general physical exam. The exam may provide some clues about what could be causing the problems, and will help guide decisions about tests that may be needed.


It may be helpful to take blood samples, X-rays, and other tests to sort out the cause of lack of appetite and weight loss.

What you can do

Family and friends often find a person’s complete lack of appetite and weight loss worrisome. It is a natural instinct to encourage the person to eat and drink more, thinking that the person will feel stronger and live longer.

However, people with advanced illnesses can be comfortable with little or no food intake for weeks or months. That is because people who are seriously ill often do not experience hunger or thirst in the way that healthy people do. Forcing someone to eat in these situations can make them feel nauseated and may contribute to feelings of distress. 

TIP: The person is often in the best position to make the decisions about what to eat, when to eat or whether to eat or drink at all.

Caregiver tips

  • Prepare several small meals during the day, as opposed to three larger ones.
  • Avoid spicy foods if the person can no longer tolerate them.
  • Avoid cooking odours if they are troublesome.
  • Do not be surprised if the person craves certain foods some days, and has no interest in them on others.
  • Try not to get frustrated if the person asks for a certain food and then loses interest by the time the food arrives.
  • Let the person decide how much, what, and when they will eat.
  • Recognize that individuals with serious illnesses often become full quickly, sometimes after just a few bites of food.
  • Try not to push the person to eat more, as a feeling of fullness, nausea or vomiting may result.
  • Try not to make mealtimes a time of tension about eating and food. Rather, focus on sharing time together.
  • Remember that a rejection of food is not a rejection of you.
  • Unless a health provider asks for updates on weight, do not routinely keep track of weight.

Mouth care

Feelings of having a dry mouth can be taken care of by sucking on ice chips, hard candies, and by providing good mouth care. The mouth can be moistened by swabbing with water or a solution of salt and water. Another option is to spray a mist of water into the mouth. Remember that as people become weaker, they may not be able to swallow liquids safely. When in doubt, check with the health care team about what is safe to offer.
See also: Care of the Mouth

What your health care team can do

The health care team will sometimes find problems that may be contributing to loss of appetite. These are problems that the health care team may want to treat:

  • constipation
  • blockage of the bowels
  • side effects of medicines
  • chemical imbalances of the blood such as a high calcium level.


The health care team might select a drug or combination of drugs to help manage lack of appetite and weight loss.

Medications that may help nausea
Medications might be used to help manage the persistent nausea that some people experience. Metoclopramide (Maxeran®) and domperidone (Motilium®) are medications that help to manage persistent nausea by speeding up the rate at which food moves out of the stomach. They also work at the nausea centre in the brain.
See also: Nausea and Vomiting

Medications that may help to stimulate appetite
Sometimes medications can help to stimulate appetite. Unfortunately, despite improved appetite and increased intake of food, the body still does not seem to be able to use the nutrients in food, so there may not be a gain in strength or improved overall survival time. However, these medications may result in more energy and an improved overall sense of well being. The medications most commonly used are steroids and special hormones called progestational drugs.

  •  Steroids such as prednisone and dexamethasone may stimulate the appetite for a short period of time (usually less than a month). This increase in appetite is usually not associated with weight gain. Side effects of long-term use of steroids may include confusion, muscle weakness, high blood sugars, and harm to bones.
  • Hormones, specifically progestational drugs such as megestrol acetate (Megace®) may also stimulate the appetite, and the effects may last longer than those of steroids. People taking megestrol acetate may gain weight, although this tends to be fat, rather than muscle tissue. Potential side-effects include the development of blood clots in the veins, increased blood sugar levels, and women may experience breakthrough vaginal bleeding. 

Antidepressant medications
Poor appetite is a common problem in people who are depressed. Antidepressant medications may be prescribed if depression is thought to be contributing to the lack of appetite. In addition, some antidepressants are thought to have appetite-stimulating effects that are independent of their influence on mood.

Tube feeding, intravenous fluids and nutrition

Sometimes when eating and drinking are not possible, fluids as well as calories and nutrients in food may be given through feeding tubes. Nutrition may be administered using tubes inserted through the nose or through the skin of the abdomen into the stomach or intestine. This is called enteral feeding, or more commonly tube feeding.

Fluids and nutrients may also be given through an intravenous (total parenteral nutrition or TPN) if the digestive system cannot absorb food. This is very different than simply giving fluids and diluted sugar as is commonly seen with an intravenous drip. TPN provides proteins, fat and carbohydrates and requires a special type of intravenous line that is inserted into a large vein, directed close to the heart (a central line). There are potential complications associated with this kind of line (such as blood clots or infections), as well as with the nutrients provided in TPN (such as liver damage). It is by no means a simple treatment, and it is only provided through careful consideration.

Using feeding tubes or intravenous (TPN) feeding are medical treatments that may be considered when there is a temporary barrier to eating and drinking, such as a fixable problem with the digestive system. Sometimes these threatments are also used to strengthen someone before chemotherapy or surgery.

Unfortunately, if a person is losing weight because the overall condition itself has made the body unable to process nutrients, then giving nutrients by feeding tubes or intravenously will not help. It is like filling a warehouse with materials, but not having a factory to turn them into something useful. In addition, the risks related to these treatments may result in complications that are harmful.

Decisions about use of feeding tubes or intravenous nutrition involve speaking with the health care team about what the overall goals of this treatment are, and whether these goals can be achieved. For example, the hope might be for weight gain, improved strength and energy, or prolonged survival time. It may be clear that these goals cannot be achieved by giving more calories, or alternatively the goal may be possible, though with some risk of complications. These considerations should be explored with the health care team.

Content reviewed May 2019

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