Scientists have discovered that your hypothalamus, a small gland on top of the brain stem (the part of the brain that connects to the top of the spinal cord), seems to house your appetite controls.

In this area of the brain, hormones and other chemicals control hunger and appetite. For example, the hypothalamus releases neuropeptide Y (NPY), a chemical that latches onto brain cells and then sends out a signal: More food!

The satisfying feeling of fullness after eating is called satiety, the signal that says, okay, hold the hot dogs, I’ve had plenty, and I need to push back from the table.

Other body cells also play a role in making your body say, “I’m full.” In 1995, researchers at Rockefeller University discovered a gene in fat cells that directs the production of a hormone called leptin (from the Greek word for thin). Leptin appears to tell your body how much fat you have stored, thus regulating your hunger (need for food to provide fuel).

Leptin also reduces the hypothalamus’s secretion of NPY, the hormone that signals hunger. When the Rockefeller folks injected leptin into specially bred fat mice, the mice ate less, burned food faster, and lost significant amounts of weight.

Eventually, researchers hope that this kind of information can lead to the creation of safe and effective drugs to combat obesity.