A video about Jeffrey Friedman and the discovery of leptin. https://www.youtube.com/watch?v=HRTiVtvvt2E
Article about how stress and sleep are related to hormones such as leptin and ghrelin and how it relates to body weight management. http://www.washingtonsblog.com/2012/04/overweight-people-arent-lazy-theyre-under-too-much-stress-and-are-sleeping-too-little.html