While a caloric restriction does lead to weight loss, a study done a few years ago examined the effects of sleep on participants already on caloric restrictions for 8 weeks, where one group slept their normal amount (~6.5 hrs per day) and another group slept ~1hr less 5 days of the week then make it up on the weekends:



The study found that while both groups lost a similar amount of weight, the group that slept normally had ~83% of their weight loss come from fat, while the group that was also on a sleep restriction lost ~85% of their weight from lean body mass. So if you're not only looking to lose weight, but to lose the right kind of weight, make sure you're both eating at a slight caloric deficit and getting adequate amounts of sleep.