New York: Do you often have difficulty sleeping? Take care, lack of sleep it can cause obesity. Lack of sleep causes the day was getting longer. Not only that, even a slow metabolism so the body uses less energy. Journal of Clinical Nutrition American and European studies says that lack of sleep can cause weight gain. Not only increase hunger, but also reduce the speed of the rhythm of burning calories. Christian Benedict, one of the researchers from the University of Uppsala in Sweden revealed that sleep a lot can prevent weight gain. "Our findings indicate that lack of sleep a night can acutely reduce energy expenditure in healthy men, which suggests sleep contributes in regulating the human energy expenditure during the day," he wrote. Previous research linking sleep deprivation with weight gain and also showed that disrupted sleep is also disturbing levels of stress and hormones associated with hunger during the wake. To help identify the exact mechanism of why lack of sleep can cause these effects, Benedict and several university colleagues examined 14 students in a series of "conditioning" sleep - no sleep, sleep is limited, and normal sleep - in a few days, then measured changes the amount of food consumed, blood sugar, hormonal levels and measure the level of metabolism. The scientists found, with only one night of missed sleep the next morning your metabolism slows, reducing the energy expenditure for a number of jobs such as breathing and digesting of five to 20 percent, compared to those with adequate sleep. A group of young men also have high blood sugar levels, such as hunger-regulating hormone ghrelin, and stress hormones such as cortisol are high after a troubled sleep. However, lack of sleep does not increase the amount of food consumed by the men. Numerous studies have watched that people who slept five hours or less per day to be more susceptible to weight gain and weight-related diseases such as type-2 diabetes. But these studies do not prove that lack of sleep as a cause of weight gain. Some experts say several factors such as lifestyle and diet likely increase the risk of obesity and it's not clear whether lack of sleep causes obesity. Sanford Auerbach, head of the Sleep Disorders Center at Boston Medical Center, responded that lack of sleep is a complex problem, with drugs as well as some things that affect sleep, and urged that the findings should be further clarified. "They found that we adjust ourselves from lack of sleep and some of these adjustments could theoretically lead to obesity," he said, adding that it was not clear how a chronic lack of sleep can affect hormone levels. National Sleep Foundation, a foundation that examines sleep, suggesting that adults should sleep as much as seven - nine hours of sleep per night.