Too little sleep or too much sleep can throw your stress and regulatory hormones out of whack, and may lead to weight gain. A single night of sleep deprivation can increase levels of ghrelin (a hormone that promotes hunger), making you more likely to overeat the next day. Reduced sleep may also lead to fatigue during the day (duh) and less physical activity, which may be another reason why people who regularly don't get enough sleep tend to gain weight.
You don’t have to be the next Usain Bolt in the making to enjoy some serious belly-slimming results from hitting the track from time to time. Even a moderate-rate jog a few times a week can blast through that belly fat; in fact, a study conducted at Duke University Medical Center found that, over the course of an eight-month study, overweight adult study subjects who jogged 12 miles a week lost the most belly fat and burned 67 percent more calories than participants who did an equivalent amount of resistance exercise, or a combination of cardio and resistance work.
It’s impossible to target belly fat specifically when you diet. But losing weight overall will help shrink your waistline; more importantly, it will help reduce the dangerous layer of visceral fat, a type of fat within the abdominal cavity that you can’t see but that heightens health risks, says Kerry Stewart, Ed.D. , director of Clinical and Research Physiology at Johns Hopkins.
"When we’re lacking in sleep, our body’s hormones get thrown off balance which can impact our hunger levels the next day. We all have two hormones that affect our appetite: ghrelin and leptin. When we don’t get enough sleep, our ghrelin levels (the hormone that makes us feel hungry) rise, and our leptin levels (the hormone that makes us feel full) drop. This means that when we’re awake, we tend to eat more but feel less satisfied. Try going to bed a little earlier than usual to avoid this imbalance and remember to remove any distractions that might prevent you from nodding off."