Evidently, there is a study that just came out on the subject. I think they just compiled a bunch of data and noted the correlation. Perhaps in the future they will model a study around it.

How to lose weight the easy way: go to sleep for longer

The Christmas break killed my sleep patterns. I have been having trouble getting to sleep before 11pm. bleh. I don't feel so well as a result. (Easier to blame the Christmas Bloat on not sleeping than on overeating )