The Natural Body Mechanism of Feeling Full
Fullness is a sense of satisfaction experienced after eating. Hunger and satiety depends on a complex feedback loop involving many hormones and other substances secreted from the gut which interact with the control centers in the brain. Mechanical contact of food with the mucosa of the stomach and small intestine muscles stimulates secretion of gut peptides, and glucagon-like peptide-1 (GLP-1), which participates in the hunger- satiety circuit.
Cholecystokinin is said to suppress appetite in humans. At the brain level, CCK inhibits food intake. When a partially digested food enters the duodenum, the cells secrete cholecystokinin. Cholecystokinin then stimulates the secretion of numerous enzymes to aid digestion. Cholecystokinin acts to slow down gastric emptying promotes a feeling of fullness and satiety. It therefore limits the desire for further food intake.
Cholecystokinin and GLP-1 are key hormones for appetite control and satiety. Hence these gut peptides control our feeling of fullness.
Leptin is also a hormone secreted by the adipose tissue. The role of leptin is to increase satiety and regulate appetite. Although numerous genes are involved in obesity, the ob gene has received much attention. The ob gene produces leptin, and it is said that the mutations in the mouse ob gene may be one of the genetic causes of obesity. Therefore small defects in the expression of the satiety signals could contribute to weight gain.
