As obesity becomes one of the greatest threats to the health of the developed world, it is essential to understand the mechanisms of appetite regulation. Recent evidence suggests that certain hormones have a physiological role in controlling satiety via the hypothalamus. With this realization has come increased efforts to understand the intricate interplay between gut hormones and the central nervous system, and the role of these peptides in food intake regulation through appetite modulation. Hormone-based therapies has potential to offer a safer approach to combat the obesity epidemic. This review focuses on the study of these hormones and disorders caused by their deficiency.