Staying in bed might not be something that springs to mind when we think of great ways to lose weight. But actually, adopting a good sleep pattern is a step in the right direction for getting in shape, according to various modern studies. Here is a quick look at some of the reasons why getting a good night's kip can set you up for healthier days ahead. Curious correlations We're all familiar with news about rising obesity levels in the developed world. A lot of this is put down to modern dietary habits, the easy availability of fast food, and a general predisposition towards inactivity. But there is another factor that suggests these reasons aren't the full story. The average number of hours that people sleep in the developed world has dropped at about the same rate as our weight has increased. Think that might be a coincidence? A study at the University of Texas studied pairs of twins to determine if there might be a connection with weight gain and lack of sleep. The conclusion was a resounding correlation between lack of sleep and weight gain. The science In the 90s, scientists discovered a hormone called leptin, which helps to regulate fat in the body and control appetite. It's not known exactly how levels of leptin are controlled, but what is clear is that with less sleep, the levels drop. This means that you're more likely to retain fat, and to feel hungry too. In addition to this, there is another hormone called ghrelin that promotes appetite, especially for calorie dense food. These hormones are in an antagonistic relationship, so when leptin drops, ghrelin levels seem to go up. The net result is that you're more likely to crave food with a high calorie content, and that you're more likely to retain those calories as fat. The solution? This is all a fairly recent field of study. But there are some general conclusions that you can make from it, namely that a good night's sleep is important in maintaining a good diet. So make sure you have a comfortable place to sleep, and a good night-time routine, to keep you healthy and in tip-top shape.