Food ingestion and digestion are essential functions of the organism, and many factors regulate hunger and satiety. The associated processes result from the interplay between the human brain and the gastrointestinal tract, or GIT for short. Researchers believe that various gastrointestinal mechanisms, namely motilin release and gastric accommodation, are key factors regulating hunger and satiety (Tack et al., 2021). The connection between the brain and the GIT, which is responsible for the ingestion and digestion of food, is a bidirectional signaling pathway (Tack et al., 2021). Thus, when the GIT lacks food, it generates a specific signal and sends it to the brain to stimulate food intake. After this process has started, people tend to feel hungry. According to Tack et al. (2021), this feeling “is expected to be maximal before the start of the meal” (p. 728). During the food intake process, satiation increases while hunger is lowered, and they both contribute to determining the point where the further intake of food should be stopped.
The GIT controls different processes contributing to two significant aspects controlling the food intake. Those aspects determine the amount of food required during a meal and the moment of the return of hunger to stimulate the ingestion of the next meal. The GIT is a unique mechanism that can sense the presence and absence of nutrients and their exact amount, significantly influencing food intake (Tack et al., 2021). Overall, the feeling of hunger invokes the desire to eat, and the following process of satiation leads to satiety, and when it fades, the hunger eventually returns. This cycle never stops and is controlled by the interplay of the brain and the GIT.
Reference
Tack, J., Verbeure, W., Mori, H., Schol, J., Van den Houte, K., Huang, I. H., Balsiger, L., Broeders, B., Colomier, E., Scarpellini, E., & Carbone, F. (2021). The gastrointestinal tract in hunger and satiety signalling. UEG Journal, 9(6), 727-734.