Appetite: Definition, Aspects Involved in This Instinctive Drive, Medical Conditions Affecting It, and More

It basically  refers to our desire to eat.

It is controlled by a complicated interplay of hormonal signals that originate from fat cells, cells of the pancreas, and cells of the intestine. These signals are also processed through cognitive and emotional filters.

The body is not just a container for calories that can be added and subtracted. We are driven by a complex game of chemists who organize food intake, desire, and food associations.

The foods we crave are a product of physiology and psychology. Appetite is different from hunger. Hunger is our physical need to eat.

You may want to eat but you don’t need to eat (for example, wanting to eat dessert after a big meal). Or you may need to eat but don’t want to eat (for example, losing interest in food when stressed).

Why is appetite regulation important?

If we overindulge or eat too much, problems arise. We can be malnourished, obese, lose reproductive capacity and / or develop diseases.

For those who want to reduce body fat, a conscious restriction of energy intake is generally unsuccessful (more than 90% of the time the weight is regained, and somewhat more).

On the other hand, some people are successful in losing fat. Why does the first group fail and the second group succeed?

Appetite is governed by two organ systems in the body, the endocrine system and the nervous system; their connection is sometimes known as the ” neuroendocrine system .”

The endocrine system and appetite

The largest endocrine organ in the body is the gastrointestinal tract. Yes, your instinct is the biggest hormone player on the block. It produces and processes all kinds of hormones, from neurotransmitters to anabolic storage hormones and sex hormones.

The organs of the endocrine system are sensitive to changes in the body and, in response to these changes, send out messengers (called hormones) to tell the body how to respond. These energy regulating hormones are classified as short or long term.

The vagus nerve is the key connection between the gut and the brain .

Several hormones play a role in appetite regulation and energy balance.

The nervous system and appetite

The nervous system works through nerve impulses and neurotransmitters (hormone-like chemicals), directing nerve tissues, smooth muscles, and other organs in the body to move, mix, and propel food that enters the digestive system.

While appetite control originates from nervous and hormonal connections between the digestive system and the brain, the digestive system has its own localized nervous system, called the enteric nervous system.

It is the “mini-brain” found in your gut. In this mini-nervous system, neurotransmitters are released, which can transmit, amplify, and modulate different signals between cells in the body.

What Causes a Loss of Appetite?

Anyone can experience a loss of appetite and for many different reasons. People may have less desire to eat, lose interest in food, or feel nauseous at the thought of eating.

Along with loss of appetite, a person can also experience fatigue and weight loss if they are not eating enough to support their body.

Causes and other symptoms of loss of appetite

Digestive problems can make a person lose their appetite.

A loss of appetite can be physical or psychological. It is often temporary due to factors such as infections or digestive problems, in which case the appetite will return when a person has recovered.

Some people may also lose their appetite as a symptom of a long-term medical condition, such as in the later stages of a serious illness, including cancer. This is part of a condition that doctors call cachexia .

The medical term for a complete loss of appetite for a longer period of time is anorexia . This is different from anorexia nervosa eating disorder, which is a mental health problem.

Next, we look at the possible causes of loss of appetite.

Common causes

Common viral or bacterial infections, such as the flu or gastroenteritis , are often to blame for loss of appetite. A person’s appetite usually returns when he begins to recover.

Common short-term causes of feeling a loss of appetite include:

  • Colds.
  • Gripe.
  • Respiratory infections.
  • Bacterial or viral infections.
  • Constipation .
  • An upset stomach
  • Digestive problems.
  • Acid reflux
  • Poisoned food.
  • Allergies
  • Food intolerances.
  • A stomach infection or gastroenteritis.
  • The pregnancy.
  • Hormonal imbalances
  • Stress .
  • Side effects of medications.
  • Use of alcohol or drugs.
  • Hyporexia

People with sore mouths, such as sores, may also experience a loss of appetite if eating becomes difficult.

Medical conditions

Long-term medical conditions can cause loss of appetite for a variety of reasons that vary depending on the cause. Loss of appetite can be related to decreased immune system function, malaise, and an upset stomach.

Medical conditions that can cause a loss of appetite include:

  • Digestive conditions, such as irritable bowel syndrome and Crohn’s disease.
  • A hormonal condition known as Addison’s disease.
  • Asthma.
  • Diabetes.
  • Chronic liver or kidney disease.
  • High levels of calcium in the blood.
  • HIV and AIDS.
  • Underactive thyroid or hypothyroidism.
  • Overactive thyroid or hyperthyroidism.
  • EPOC.
  • Heart failure.
  • Stomach or colon cancer
  • Side effects of medications.

Loss of appetite is a common side effect of many medications, along with other digestive problems, such as constipation or diarrhea. This is common when the drugs pass through a person’s stomach and digestive tract.

Medications and treatments that often cause a loss of appetite include:

  • Sedatives
  • Some antibiotics
  • Immunotherapy.
  • Chemotherapy.
  • Radiation therapy to the stomach area.

If people have recently had major surgery, they may experience a loss of appetite after the operation. This feeling may be related in part to anesthetic medications.

Recreational use of drugs, such as cocaine, cannabis, and amphetamines, can also cause loss of appetite.

Psychological causes

Psychological factors and mental health conditions can have a significant impact on a person’s appetite. These may include:

  • Depression .
  • Anxiety.
  • Panic attacks.
  • Stress.
  • Pain.
  • Eating disorders, such as bulimia or anorexia nervosa.

A loss of appetite can also be more common in older adults. This may be due to increased use of medications and changes in the body as you age. These changes can affect:

  • The digestive system.
  • The hormones.
  • The sense of taste or smell.
Some cancers

A loss of appetite or unexpected weight loss can sometimes be a symptom of certain cancers, such as pancreatic, ovarian, or stomach cancer.

Along with loss of appetite, people may experience the following symptoms:

  • Stomach aches.
  • Acidity.
  • Feeling full quickly.
  • Yellowing of the skin or eyes.
  • Blood in your stools.

If people experience any of these symptoms, they should see a doctor who will be able to find out the underlying cause.

Loss of appetite and serious illness

A person should see a doctor if they are vomiting for more than a day and have a total loss of appetite.

People with serious medical conditions may experience a loss of appetite that may be due to the disease itself or as a side effect of treatments, such as chemotherapy treatment for cancer.

Some people in the later stages of serious illness may experience cachexia .

Cachexia is the term for weight loss, muscle loss, and general poor health caused by chronic, life-limiting diseases.

People with cachexia can get nutritional advice from their doctor, who can help create a nutritional plan to make sure they are getting the necessary calories and nutrients.

A person with a serious illness should see their doctor if they have a complete loss of appetite for a day or more or any of the following:

  • Vomiting for a day or more.
  • Inability to retain fluids.
  • Pain when trying to eat.
  • Irregular urination


A doctor may prescribe certain medications to help increase appetite and reduce other symptoms, for example nausea.

If depression or anxiety is causing people to experience a loss of appetite, talk therapies and sometimes antidepressants can help.

If a doctor believes that a specific drug is a reason for losing your appetite, they may be able to change the dose or drug.

Home remedies

People may find it easier to eat several small meals a day rather than three larger meals.

Try to make these foods high in calories and protein to ensure that the body receives plenty of nutrients and energy. People may also find that having liquid foods, such as protein shakes and drinks, is easier to take.

Adding herbs, spices, or other seasonings to foods can also encourage people to eat more easily. Eating meals in relaxed or social settings can make eating more enjoyable.

People can also continue to drink plenty of fluids to prevent dehydration. Gentle exercise, such as a short walk, can also sometimes increase your appetite.