Research has documented the link between obesity and sleep loss, although no on has been able to explain why.
Recent research has found that sleep deprivation significantly decreases brain activity related to the evaluation of appetite and affects choices of what kind of foods we find desirable (Greer SM, et al. 2013).
The result is an increase in the desire for food that causes weight gain and is high in calories. Not sleeping enough can cause you to gain weight, for these reasons. It can also be one of the reasons why you maintain the gained weight. If you want to stay lean or lose weight, be sure to get enough sleep. Most people need between 7 and 8 hours.