leptin was recently discovered in 1994 by jeffrey m. friedman and colleagues at rockefeller university. its discovery is important in the study of obesity which has become a problem in western society. the importance of leptin was discovered through experiments done on mice in a laboratory. scientists found that mice who had more leptin in their bodies were thinner and didn't need to eat as much. leptin levels can be increased by reducing stress and having quality or restful sleep.