Neurobiology

Hunger and body weight are negative feedback loops regulated by the brain. The cycles are controlled by leptin and grellin hormones. Leptin POMC neurons signal for satiety by producing alphaMSH. AGRP neurons signals for hunger. The leptin hormone is produced by fat stores and excites the POMC neurons, signals for satiety. Leptin activates AGRP neurons, signaling for hunger. This corresponds with the hunger-sateity curve. When energy is high, fat stores release leptin to signal sateity. When energy is low, the gut releases ghrelin to signal hunger. This allows the brain to regulate when we eat based on energy and food stores.