Leptin is a hormone produced in the fat cells in the body. One of leptin’s primary roles
is regulating appetite and body weight. The hormone tells your brain what to do with the energy it has, according to Dr. Mercola. Leptin and insulin work hand in hand. Leptin is largely responsible for the accuracy of insulin signaling and whether or not you become insulin resistant. Exercise is one of the fastest and best ways to lower your insulin and leptin resistance.