There is a region in the brain that controls hunger by releasing both hunger and satiety chemicals. Signals from the hormone leptin makes you feel full and satisfied, signals from the hormone ghrelin makes you want to gorge. When you don’t get enough sleep, it drives leptin levels down, which means you don’t feel as satisfied after you eat.Lack of sleep also causes ghrelin levels to rise. This means appetite is stimulated so you want more food.
For more scientific studies on this fact go to: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2710609/