It begins by explaining how food is converted to energy in the body, including the role of the hypothalamus, glucose, and the hormones insulin, ghrelin, and cholecystokinin. Next, working from an evolutionary perspective, the researchers explain how weight regulation is complicated by advertising, readily available fast food, and other environmental cues that encourage overeating, especially of foods high in sugar, salt, and fat. The video ends with a brief discussion of childhood obesity, and the importance of good health policies in attacking this epidemic, including higher prices for unhealthy foods and smaller portion sizes.