Nowadays people sleep a lot less than before. In addition to making you tired, it also doesn't help with losing weight. Researchers tracked the weight of 275 men and women (ages 21 to 65) for 6 years. Each person gained a little weight in those 6 years. Those who slept 5 to 6 hours gained about 3 kilos more than those who slept 7 to 8 hours. You make 5 percent less leptin per hour that you sleep less. Leptin is an appetite suppressant hormone. And 5 percent more ghrelin, also known as the hunger hormone. Sleep apnea also has a lot of influence on the quality of sleep and can therefore also be a cause of why you don't lose weight. Night rest is therefore very important with weight loss.