One means to keep functioning while sleep deprived is to eat more. I don't think it's really poor impulse control per se. It's a coping mechanism, sort of like the body shunting waste gas through the kidneys at high altitude because you can't offload them all via breathing out and they have to go somewhere, but that's not really the optimal way to do that and it has knock on effects because urinating to remove them also drags salt and other stuff with it, thus the need to drink more and get more electrolytes at altitude. (Edit: implicitly, weight gain us the equivalent knock on effect for eating more while sleep deprived.)