Sometimes people still claim that dieting is purely a matter of willpower. However, while a little motivation is certainly important, your body can be a real nuisance! The hormone ghrelin is one of the main players in this phenomenon. Ghrelin is also known as the hunger hormone, and that nickname tells you exactly what it does. It signals your brain that you need to eat something. Ghrelin is produced in the stomach wall. Once the stomach is empty, this production begins. The hormone then flows through the blood to the brain, signaling that food is needed. Result: you feel hungry and start looking for food. Once your stomach is filled, ghrelin production stops. Instead, your body starts producing leptin, the hormone that makes you feel full. This means you don’t have to eat until your stomach is empty again – a process that, in theory, should ensure you get just enough to eat. Overeating surgeries remove part of your stomach or make your stomach release less of the hunger hormone, and as a result, you eat less.