The two hormones responsible for controlling the sensation of hunger are leptin and ghrelin. Leptin, also referred to as the “satiety hormone”, makes the body avoid food cravings and gives the person a feeling of being full. Calorie burning, food intake and metabolism are regulated by this hormone. It signals the brain when the stomach is full and when there is a need to stop eating. It also indicates when the energy created by the body can be used. The messages it sends travel from the hypothalamus to the thyroid gland.
Discovered in 1994, leptin is a hormone produced by fat cells and can only be found among mammals. It is a protein product with 146 amino acids. Insulin and cortisol increase the production of leptin.
Leptin levels are higher when a person sleeps. This is the reason why the sensation of hunger cannot be felt when one is asleep. When a person lacks sleep, it leads to a decline in leptin levels. This results in a starving feeling and the slowing down of metabolism. When a man and a woman with the same weight are compared, the woman possesses higher levels of leptin. Thus, estrogen is considered to be a major differing factor. Weight Loss – Health
On the other hand, the hormone that works in contrast to leptin is the ghrelin. It is also referred to as the “hunger hormone”. Ghrelin signals the brain when the person needs to eat. It also stops the burning of calories. Rather than converting fat into energy, ghrelin is in charge of storing the fat. The level of ghrelin drops when a person sleeps because the person does not need much energy when asleep. When a person is deprived of sleep, ghrelin levels increase which makes the body feel hungry. The situation also makes the system feel a shortage in calories so the burning of calories is stopped.
Ghrelin is released when the stomach is empty and the secretion of gastric acid is further increased by ghrelin. Discovered in 1999, this hormone interacts with the pleasure centre of brain so hunger can be stimulated. Naturally, ghrelin levels are lower before taking a meal, which causes an increase in appetite. The storage of fatty tissue in the part of the stomach is also influenced by ghrelin and metabolism and burning of fats are slowed down by ghrelin.
Although it is baffling, obese individuals have lower levels of ghrelin compared to leaner people. In addition, overweight people have higher levels of leptin than thin people.
Leptin and ghrelin therefore play significant roles in regulating food intake and energy conversion. These hormones cannot be ignored because they are necessary for vital body processes.