These habits of late sleepers -- sleeping less, going to sleep later in the night, and eating more after 8 p.m. -- were all found to be associated with a higher body mass index. Among these habits, eating after 8 p.m. was the strongest predictor of a higher BMI. What does this mean? It's not just what you eat, but when you eat, that can affect your ability to lose weight. And your sleep habits can have a significant influence on the timing of your eating, as well as on how much you eat.