Researchers suggest how much sleep and the quality of sleep we get is actually directly related to hormones that can influence our weight. Leptin and Ghrelin work together to control the appetite and feelings of fullness. So what's the connection? When we don't get enough sleep, Leptin levels decrease, therefore leaving us not feeling satiated. Not enough sleep can actually cause Ghrelin levels to increase, which then stimulates our appetite. The combination of the two can lead to overeating, which can lead to being overweight.