Appetite is a person’s desire to eat food. It is distinct from hunger, which is the body’s biological response to a lack of food. A person can have an appetite even if their body is not showing signs of hunger, and vice versa.
A person’s appetite can rise and fall due to a wide range of factors, sometimes causing people to eat less or more than their body needs.
In this article, we look at appetite in more detail, including the factors that can affect it, how to increase or decrease it, and when to see a doctor.
Appetite is a person’s general desire to eat food. A person’s appetite might dictate how much food they want to eat, as well as the type of food they feel like eating.
Hunger occurs when the body recognizes that it needs more food and sends a signal to the brain to eat. The signs of hunger often include:
- rumbling or gurgling in the stomach
- a feeling of emptiness in the stomach
- feeling lightheaded or dizzy
- trouble concentrating
According to the Canadian Society of Gastrointestinal Research, a person is less likely to have a preference for what they want to eat when they are hungry. In contrast, someone with a desire to eat may find that specific factors increase their appetite. These may include:
- boredom, stress, or another heightened emotional state
- seeing or smelling food that appeals to them
- routine, habit, or a special occasion
Health conditions, medications, and environmental factors can also change a person’s appetite. Lifestyle factors and health conditions can affect hunger, as well.
A wide range of factors can affect appetite. We look at some common examples below:
In a 2017 study on the ketogenic, or keto, diet, researchers noted that people who start following a diet often experience an increase in appetite at the start.
However, after continuing to lose weight and staying on the diet for 3 weeks, the participants in this study no longer experienced this increase in appetite. The keto diet is high in fat and low in carbohydrates.
Other studies state that protein increases satiety and feelings of fullness after meals. A diet that contains adequate protein may, therefore, help regulate a person’s appetite.
A person’s emotional state has a significant effect on their appetite. For some people, stress or grief may cause them to eat more food as a way of coping with how they feel, but for others, these emotions have the opposite effect.
Some mental health conditions also affect appetite, including:
Binge eating disorder involves periods of excessive overeating, which feelings of guilt and shame then follow. A person with this disorder may strongly desire food and eat it even though they are not hungry. Anorexia nervosa, which causes someone to restrict their food intake, may reduce the person’s desire to eat even though their body needs food.
- eating smaller meals more frequently
- eating foods with high energy values, such as fruit, nuts, and cheese
- preparing smoothies at home that contain plenty of energy and nutrients
Pregnancy can also increase appetite by causing cravings. A 2014 study suggests that cultural norms have an effect on what foods women may crave during pregnancy, which may lead to overeating.
Numerous medications can affect a person’s appetite. Some medications that can cause weight gain include:
- blood pressure-reducing medications, such as metoprolol (Lopressor)
- some epilepsy medications
- certain diabetes medications
- antipsychotic medicines
- steroid hormones, such as prednisone (Deltasone)
- certain antidepressants, such as paroxetine (Paxil) and sertraline (Zoloft)
Many medical conditions can cause a person to lose or gain appetite, including:
- Infection: Bacterial or viral illnesses, such as viral gastroenteritis, can temporarily reduce a person’s appetite.
- Thyroid disease: The thyroid has a significant effect on appetite. If someone has hyperthyroidism or hypothyroidism, they may notice an appetite increase or decrease.
- Cancer: Cancer can sometimes cause a direct loss of appetite, depending on the symptoms, as well as the location of the tumor and whether it releases hormones. It can also cause indirect loss of appetite due to a person’s response to treatment.
- Parkinson’s disease: According to the Parkinson’s Foundation, this condition can cause a loss of taste or smell, which may reduce someone’s appetite.
- Kidney disease: If the kidneys start to fail, certain waste products will build up in the bloodstream. This buildup can lead to a lack of appetite.
If a person has a low appetite due to an underlying medical condition, treating the condition may improve it.
For longer term causes of low appetite, such as cancer, the Pancreatic Cancer Action Network (PanCAN) suggest that people adjust their eating habits to increase their desire for food by:
- eating foods that look and smell appealing
- using aromatic spices and herbs to improve the flavor
- making meals enjoyable by playing music and presenting the food in an attractive way
- eating smaller, more frequent meals throughout the day
- eating at consistent times each day
- planning meals the day before
- drinking plenty of liquids
As other lifestyle factors, such as sleep, exercise, and stress, also influence appetite, PanCAN recommend:
- getting enough rest
- getting regular exercise
- taking medications to reduce nausea, if appropriate
A person who finds that they want to eat more food than their body needs can reduce their appetite by addressing the underlying cause.
The Obesity Medicine Association also recommend mindful eating. People can practice mindful eating by:
- waiting until they are moderately, but not ravenously, hungry
- avoiding distractions, such as the TV, during meals
- taking five deep breaths before eating
- using their senses to appreciate how the food looks, smells, and tastes
- taking small bites and chewing thoroughly
- paying attention to the body’s signs that it is full
A person can adjust what they eat to increase feelings of fullness by avoiding processed foods and simple sugars. Instead, they can focus on meals that contain a balance of protein, healthful fats, fiber, and carbohydrates.
In a 2018 study, researchers found that drinking water before a meal helped reduce the number of calories that the participants ate during the meal. Although this may not directly affect appetite, it might help reduce hunger.
A person should talk to their doctor if they experience unexplained appetite changes, in case an underlying health condition is affecting their appetite. A doctor can also help someone switch medication if its side effects are responsible for appetite changes.
A person with a mental health condition that makes them want to overeat or severely limit their food intake should talk to a doctor or therapist for support.
Appetite describes a person’s desire to eat. Many factors can affect someone’s appetite, including their environment, lifestyle, mental health, and physical health.
Mindful eating can help someone pay attention to when the body needs food. However, if a person with a high or low appetite suspects that there is an underlying cause, they should speak to a doctor.