What makes me feel hungry?

When your stomach is empty, its inner lining releases this feisty little chemical called ghrelin. When your stomach is growling, it’s this gremlin of a hormone that’s sending desperate messages that you need more food. Ghrelin makes you want to eat. When you diet through deprivation (not eating enough food), the increased ghrelin secretion sends even more signals to eat, overriding your willpower and causing chemical reactions that give you little choice but to go crazy in the pantry. Your stomach secretes ghrelin in pulses every half hour, sending subtle chemical impulses to your brain--almost like subliminal biological messages: Cheese fries! Milkshake! Triple burgers! When you’re really hungry, those messages come fast--every twenty minutes or so--and they’re also amplified. So you get more signals and stronger signals that your body wants food. After long periods, your body often can’t ignore those messages. The chemical cattle prod stops when you eat; when your stomach fills, your ghrelin levels go down, thus reducing your
appetite.