I've always said that at a certain point, sleep and food are interchangeable. I learned this back in my first run through college during the many sleepless nights I spent studying. I also find the same thing happens when I'm up late programming. If I'm missing a few hours sleep, I try to replace the missed hours of sleep with a full meal. Now, there's a study that proves me right.
Losing sleep can raise levels of hormones linked with appetite and eating behavior, the researchers said... we are finding that people tend to replace reduced sleep with added calories.
So, keep that in mind the next time you're burning the midnight oil.