Ghrelin is a hunger hormone, chiefly secreted by the stomach and in small amounts by the pancreas, small intestine and brain. The main role of ghrelin is to stimulate appetite, increase intake of food and store fat. Ghrelin levels stay at the peak before eating and low up to an hour after the meal. Interestingly, if you want to go on a diet the first step is to eat ghrelin-suppressing foods. Here are the 5 best appetite suppressants.