Even if you don't eat late, sleeping less than 7 hours a day is associated with weight gain (Lyytikäinen et al., 2011) because the lack of sleep alters the balance of hormones that regulate appetite and satiety (Knutson & van Cauter, 2008; van Cauter et al., 2007)
I read about this too in the research journal I cited in this post. It's amazing how the body works.
Thanks so much for contributing.