New research suggests that the hunger hormone ghrelin is activated by fats from the foods you eat, not those made in your body, in order to optimize nutrient metabolism and promote the storage of body fat.
The findings could turn the current model about ghrelin on its head and point to a novel stomach enzyme (ghrelin O-acyl transferase, or GOAT) responsible for the ghrelin activation process.
Ghrelin is a hormone that was believed to accumulate during periods of fasting, and it is found in the body in high concentrations just before meals. It is dubbed the "hunger hormone" because it has been shown to stimulate hunger and increase food intake in animal models and humans.
Originally it was assumed that the fatty acids attached to ghrelin were produced by the body during fasting. The new data suggests that the fatty acids needed for ghrelin activation actually come directly from ingested dietary fats. The ghrelin system may therefore be a lipid sensor in the stomach that informs the brain when calories are available, giving the green light to other calorie-consuming processes such as growing.