Every organism needs a sufficient supply of energy in order to be able to carry out the body processes properly. Everything that it ingests through food is processed in the body and used as energy for everyday life. If a person - or another living being - does not provide the body with sufficient nutrients, sets hunger or the feeling of hunger. There is a difference between hunger and appetite.
What is hunger
Hunger is a warning signal from the body. It is a sensation triggered by the brain that is perceived as unpleasant, which causes the person concerned to ingest food.
The sensation is controlled by neurotransmitters in the hypothalamus (diencephalon). This is the main control system of the central nervous system, which is responsible for the entire function and maintenance of the internal organism.
The feelings of hunger and satiety are controlled by complex interactions in the body, which to this day not all have been adequately researched. Insufficient filling of the stomach is indicated by stomach growling, but does not in itself trigger the familiar feeling of hunger. The glucose and insulin amounts in the blood serve as markers for this.
If a person does not provide the body with sufficient nutrients, this has fatal consequences in the long run, which in extreme cases can result in starvation. This is no longer to be feared in industrialized countries, whereas people in poor countries of the world may still be threatened by famine.
The knowledge of food intake as a hunger-reliever measure is anchored in the body of living beings. Animals, too, have the instinct to go hunting regularly to prevent starvation. Some animals create supplies for hard times or winter so that they don't have to go hungry during these times.
It is not just hunger that makes people eat. In this way, socialization and society have made food a stimulant that also has other purposes than ensuring survival. Therefore, appetite as a psychological phenomenon must be distinguished from hunger.
Function & task
The function of feeling hungry is to ensure that the body is adequately supplied with nutrients. This goes hand in hand with the feeling of satiety, which occurs when hunger is satisfied and shows people that there is sufficient nutrient intake.
Without the feeling of hunger, there would be a risk of insufficient nutrition for the body. This draws the energy that is needed to carry out daily tasks from food. If the hunger is not satisfied for a longer period of time, physical complaints arise, which differ in severity and increase rapidly depending on the duration, because the body then draws on the body's own energy reserves.
How long the feeling of fullness lasts varies from person to person and depends on various factors. This includes on the one hand the physical condition, but on the other hand also the activity. The more active a person is, the more energy they consume and need. Therefore, active people have a higher need for calories that must be covered by food.
In connection with the normal feeling of hunger, there is also cravings, which are characterized by an excessive urge to eat immediately. However, this is a process that can be described more in terms of appetite than actual hunger. Doctors differentiate between physical and psychological cravings.
There is also a mixed form of both. The former include, for example, hormonally induced cravings or those triggered by hypoglycaemia. Psychological triggers, on the other hand, can be, for example, emotional stress or various eating disorders.
Illnesses & ailments
If the feeling of hunger persists for a long time without being satisfied, the brain releases hormones that cause stress. When hungry, however, the body can also secrete mood-enhancing hormones, which to a great extent can lead to intoxicating states. There is a risk of developing various eating disorders such as anorexia or bulimia.
Permanently reduced food intake leads to depression, aggression and mood swings. In addition to the physical damage and loss of body weight, the decline in pleasure and sleep disorders are not uncommon. In the long run, the feeling of satiety is also disturbed. This can lead to food cravings.
Diseases that are associated with a disorder of the feeling of hunger and eating behavior are anorexia nervosa, binge eating (bulimia nervosa) and binge eating. In addition, a permanent lack of food leads to a so-called starvation metabolism. The metabolism changes and is forced to draw the necessary energy from its own reserves. The entire metabolism changes over a longer period of time.
Malnutrition can also impair physical and mental development, especially at a young age. Depending on the extent, malnutrition causes massive organ damage and can ultimately lead to starvation.
