Every organism needs a sufficient supply of energy to be able to carry out the body processes reasonably. Everything it takes in through food is further processed in the body and used as energy for everyday life. If a person – or any other living being – does not provide the body with sufficient nutrients, hunger or the feeling of hunger sets in. Hunger is to be distinguished from appetite.
What is hunger?
If a human being – or another living being – does not provide the body with enough nutrients, hunger or the feeling of hunger sets in. Hunger is a warning signal from the body. It is a sensation triggered by the brain, perceived as unpleasant, that causes the individual to take in 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 functioning and maintenance of the internal organism. The feelings of hunger and satiety are controlled by complex interactions in the body, not all of which have been sufficiently researched to date. 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 levels in the blood sometimes serve as markers for this. If a person does not provide the body with sufficient nutrients, this has fatal consequences in the long term, which in extreme cases can end in starvation. This is no longer to be feared in industrialized countries, whereas people in poor countries of the world can still be threatened by famine. The knowledge about food supply as hunger-satisfying measure is anchored in the body of the living beings. Animals, for example, also have the instinct to hunt regularly to prevent starvation. Some animals create stores for hard times or winter to avoid starvation during these periods. Hunger is not the only thing that makes humans eat. Thus, socialization and society have elevated food to a means of pleasure with purposes other than ensuring survival. Therefore, appetite as a psychological phenomenon must be distinguished from hunger.
Function and task
The function of hunger is to ensure that the body receives sufficient nutrients. This is accompanied by the feeling of satiety, which occurs when hunger is satisfied and indicates to the person the sufficient intake of nutrients. Without the feeling of hunger, there would be a risk of not supplying the body with sufficient nutrients. The body draws the energy it needs to perform its daily tasks from food. If hunger is not satisfied over a longer period of time, physical complaints occur that vary in severity and increase rapidly depending on the duration, because the body then draws on its own energy reserves. How long the feeling of fullness lasts varies from person to person and depends on various factors. These include physical condition on the one hand, but also activity on the other. The more active a person is, the more energy he or she consumes and needs. Therefore, active people have a higher kilocalorie requirement, which must be covered by food. In connection with the normal feeling of hunger, there is also ravenous hunger, which is characterized by an excessive urge to eat immediately. However, this is a process that can be described as appetite rather than actual hunger. Doctors distinguish between physically and psychologically induced ravenous hunger. There is also a mixed form of both. The former includes, for example, hormonally induced cravings or those triggered by hypoglycemia. Psychological triggers, on the other hand, can be emotional stress or various eating disorders, for example.
Diseases and disorders
If the feeling of hunger persists for a long time without being satisfied, the brain releases hormones that cause stress. However, in a state of hunger, the body can also release mood-altering hormones that can lead to high levels of intoxication. This is a risk for developing various eating disorders such as anorexia or bulimia. Permanently reduced food intake leads to depression, aggression and mood swings. In addition to physical damage and a loss of body weight, a decline in the sense of pleasure and sleep disturbances are not uncommon.In the long run, the feeling of satiety is also disturbed. This can lead to food cravings. Diseases associated with a disturbance of the feeling of hunger and eating behavior are anorexia nervosa, bulimia nervosa and binge eating. In addition, a permanent lack of food leads to a so-called hunger metabolism. The metabolism adjusts and is forced to draw the necessary energy from its own reserves. Over a longer period of time, the entire metabolism changes. Malnutrition can also impair physical and mental development, especially at a younger age. Depending on the extent, malnutrition causes massive organ damage and can ultimately end in starvation.
