Not getting enough sleep may alter the hormones that control the appetite.
Previous studies have confirmed that poor sleep habits lead to being overweight.
Reuters reports that a new study from a recent medical journal now explains why.
In the study, men with sleep disorders had fluctuating levels of the "hunger" hormone ghrelin, which is related to energy, metabolism and appetite control.
Night-time levels of ghrelin were 30 percent lower than day-time levels.
So during the day that hormone level rises and boosts the appetite.