Appetite refers to a person’s natural desire to eat food. Appetite is separate from hunger as we can develop this desire even when we are not specifically hungry.
What Is Appetite?
The idea of appetite is considered a natural desire that is typically associated with a sensory psychological reaction. This specific reaction stimulates an involuntary psychological response. It is not our body’s biological response to the lack of food, rather it is our general desire to satisfy an emotional, psychological and physical need, especially for food. According to a 2019 study 1 , it is “the system that influences energy intake (food consumption) and associated motivational states such as hunger.” It is closely related to energy expenditure. A healthy appetite encourages healthy eating. Although it can be influenced by hunger, certain types of foods, especially something a person likes, can boost someone’s desire to eat and stimulate hunger. It influences what type of food we may want to eat and in what quantities. It’s primary objective is to control the intake of energy based on our metabolic requirements. This desire to eat can be decreased when we feel full and satisfied after eating.
Unlike hunger, where we typically tend to eat whatever food is available, this desire can be controlled by certain factors, such as –
- Appealing or aromatic food
- Stress or sadness
- Lifestyle or certain eating habits
- Mental and physical health conditions, such as depression 2 and obesity 3
- Substance use, like marijuana
When we see or smell any delicious and tempting food, our mouth starts salivating and our stomachs contract. This condition triggers our desire to taste the food and feel its texture. Even the thought of the food is capable of eliciting the response. A 2016 research paper 4 suggests that appetite is motivated by the accessibility of food and the anticipated and experienced pleasure of eating it. The study adds, “The pleasure of eating food is similar to food reward, is determined primarily by the state of emptiness of the gut and food liking related to the food’s sensory qualities.” This primary factor separates the concept of appetite from hunger. This response refers to a conditioned reaction to food and coordination between the human brain and stomach. It doesn’t cause any physiological uneasiness such as dizziness or fatigue since it is not a physical need like hunger. However, research 5 says that it can be controlled and ignored.
Understanding The Science Of Appetite
A 1993 research paper 6 mentions human appetite as a complex mixture of a psychological and physiological phenomenon that includes –
- Total energy intake
- Ingestion of particular nutrients
- Desire to eat food
- Specific cravings
- Food preferences
It can be influenced by certain significant physical factors such as blood sugar level, hormones, and exercise, and emotional factors such as different moods, stress, loneliness. The basic concept of the desire to eat is a complex and dynamic interplay between hormones, habits, senses, past experiences, future expectations, and other substances. Many of these substances are an integral part of the mediated metabolic processes. The physiology of appetite is associated with the scientific attempt to understand eating.
The following are some of the factors that positively contribute to the ultimate signal people receive from their guts related to their general desire to eat.
1. Hormones and the brain
A 2017 study 7 has shown that several hormones and neurotransmitters that are classified as appetite stimulants and suppressants play a key role in triggering the desire to eat. Studies 8 suggest that this desire is primarily regulated by three significant regions in our brain such as the hypothalamus, the limbic center of the emotional brain, and the hindbrain.
- The hypothalamus governs the metabolic process of humans.
- The limbic center triggers dopamine for pleasure.
- The hindbrain transforms the behavior of eating into an unconscious habit.
This process creates a neural circuit that allows us to eat again and again. A 2007 research paper 9 mentions that the balance between two gastrointestinal hormones – ghrelin and leptin works as a mechanism and regulates our desire to eat. “Leptin is a mediator of long-term regulation of energy balance, suppressing food intake and thereby inducing weight loss. Ghrelin on the other hand is a fast-acting hormone, seemingly playing a role in meal initiation,” add the researchers.
2. Sensory systems
According to a 2003 study 10 , the science of appetite explains what people smell, see, taste, touch, and hear largely affects what they crave and desire. The sense of smell and sight stimulate gastric acid secretion that prepares the human to consume food. Taste and the sense of texture help to release the salivary enzymes that begin to break down the food into pieces.
3. Emotional factors
Another research 11 says that this science includes an emotional process that releases a flood of dopamine a person has been craving into their brain. However, the person feels a kind of pleasure and satisfaction in his/her after experiencing the food.
4. Human habits
This psychological and physiological process involves the concept of human habitation as well. A 2011 research paper 12 explains that a significant part of regular eating behaviors consists of human habits. It includes how frequently a person eats, how the person substitutes food for his/her emotional and spiritual needs, what time of the day the person eats, etc.
Characteristics Of Appetite
Several signs indicate that a person has an appetite, while the primary sign is the feeling of hunger. It generally occurs when the body recognizes that it needs food and sends a signal to the brain to eat. It can show itself in many ways, including:
- Rumbling in the stomach
- Difficulty in concentrating
- Craving for food
- Nausea and feeling empty in the stomach
- Dizziness or lightheadedness
People’s desire to eat is not considered constant, it differs from day to day. A 2015 research paper 13 has shown that even a person’s emotional state such as boredom, stress, excitement, and availability of appealing food may influence it.
Appetite Vs. Hunger
Research says that hunger refers to a physiological reaction that occurs due to certain biological changes in the body which indicates that you need to eat to maintain your energy levels. The researchers add, “Hunger occurs once you haven’t eaten in a while and if food is eaten properly should only occur a few times throughout the day.” Meanwhile, appetite is primarily a psychological desire to eat and often experienced in the mind. It allows one to feel certain physical sensations also such as increased salivation. Hunger can lead to appetite as well as people may feel the desire because of certain emotional or environmental conditions. If the hunger gets intense, one might feel uncomfortable or physically weak. It is very possible for one to feel physically hungry without having an appetite.
Factors That Affect Appetite
There is a wide range of important factors that hugely impact appetite. These factors can cause you to lose your desire to eat as well as lead to a caloric surplus diet. Meanwhile, getting these factors under control will make it easier for you to maintain a healthy and manageable weight. Here are the 6 most significant factors that influence this desire:
A 2017 research paper 14 says that people who start to follow a strict diet such as the keto diet, are more likely to experience an increase in their appetite at the start. What and how often we eat in a day can affect our desire to eat, however, this study states that participants didn’t experience such a thing after losing weight and staying on the diet for 3 weeks. Another study 15 has shown that protein consumption increases satiety and the feeling of fullness after a meal. Following a diet with adequate protein may help to regulate a person’s appetite.
2. Mental health condition
A person’s mood and emotional state are interlinked with their desire to eat. Certain mental health conditions such as depression 16 , stress, and some eating disorders may impact the desire.
a. Depression and anxiety
Research 2 suggests that depression can increase or decrease a person’s appetite. Depressed people tend to associate food with reward and eat more to feel better. According to a 2017 study 17 , women with a higher trait of anxiety are more likely to consume high-calorie food that often leads to a higher Body Mass Index (BMI).
Read More About Depression Here
b. Eating disorders
Studies 18 explain that binge eating disorder allows a person to consume excessive food which leads to guilt and shame. A person with this disorder may consume food even though they are not hungry. Similarly, a recent 2020 research paper 19 says that anorexia nervosa makes someone restrict their food intake even though their body needs food. “Anorexia nervosa is a psychiatric disease in which patients restrict their food intake relative to their energy requirements through eating less, exercising more, and/or purging food through laxatives and vomiting.” add the researchers.
Read More About Eating Disorders Here
3. Blood sugar level
Several studies 20 show little evidence of a causal relationship between declining blood glucose levels and human desire to eat. People tend to feel hungry when their blood glucose level is decreasing. When we consume sugar, it is shuttled into the cells to be used as an energy source and sends a signal to our brain that we need to eat.
A 2018 research paper 21 suggests that several medicines cause weight gain that is associated with people’s desire to eat. Some medicines that can lead to weight gain include:
Pregnant women may experience an aversion to certain food items and intense cravings for others. Some common complaints during pregnancy such as morning sickness, nausea, or constipation may decrease one’s appetite. According to a 2014 study 22 , certain cultural norms affect what foods women may have cravings for, which often cause overeating.
6. Medical condition
A 2008 research paper 23 says that several illnesses can have an impact on the appetite and hunger of older adults. Apart from this, diseases that can cause taste or smell loss can decrease people’s desire to eat. Such medical conditions include:
- Thyroid diseases
- Bacterial or viral infections
- Kidney diseases
- Parkinson’s disease
7. Other Social Factors
Research 24 has shown that several social factors such as social interactions are interconnected with our desire to eat. It is one of the areas that hugely contributes to the consumption of calories. It doesn’t directly affect one’s appetite, but partially in the sense that people often get influenced to consume such foods that are accessible and being eaten by others around them.
Appetite Control And Obesity
Various hereditary forms of obesity are considered to be associated with the regulation of obesity. A 2012 research paper 25 mentions that the gastrointestinal hormones ghrelin and leptin contribute to the decreased response to satiety that may promote the development of obesity. Another 2006 study 3 says that the rapid increase in childhood obesity has prompted research into the mechanism of appetite control. It shows that complex pathways in the human brain modulate the energy balance. The pathways involve appetite centers in the hypothalamus and brainstem. The hormonal signals of the energy status are released by the gut and the periphery.
How To Increase Your Appetite?
Various factors may contribute to one’s low appetite including any underlying medical conditions, any mental health problems, or even side effects of any treatment. Forcing yourself to eat while you don’t want to may just add to the stress of being sick. The following are some of the simple ways one can increase their appetite.
- Eat snacks instead of meals
- Try to consume those foods that look and smell appealing
- Improve the flavor by adding aromatic spices and herbs to your food
- Choose energy-dense foods
- Make your mealtime enjoyable with a happy and relaxed atmosphere
- Get enough sleep and regular exercise
- Eat at consistent times each day
- Drink water between meals and try to drink liquid meals
How To Control Your Appetite?
In some cases, people can feel like they want to eat more than their body needs. They can reduce their appetite by addressing the underlying diseases. Overeating because of anxiety or stress can be treated in mindfulness practice. A 2014 research paper 26 claims that mindfulness practice helps to decrease emotional eating effectively. Here are some of the ways one can practice mindful eating:
- Wait until you are moderately hungry
- Avoid distractions such as television or mobile phone during meal
- Take three to five breaths before eating
- Opt for fiber-rich foods
- Take small bites and chew your food thoroughly
- Pick solid foods over liquids
- Drink plenty of water
- Eat mindfully
Overcome An Appetite Disorder
As it is considered a human desire to eat, it is interlinked with certain body systems and can impact them either positively or negatively. A person should consult with a doctor if they experience unexplained appetite changes as it can be a sign of any underlying physical or mental health conditions also. A health specialist can help a person to switch the prescribed medication if its side effects are the ultimate cause for the change.References:
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