Body weight regulation is a complex system resulting from the interaction of peripheral signals and the central nervous system.

“it's really a product of the interaction of these peripheral signals as you refer to them including metabolites such as glucose and free fatty acids and so forth and the central nervous system not just the hypothalamus but areas that like the brainstem the amygdala the frontal cortex there's many other areas of the brain that interact with these signals to influence both the behaviors and the unconscious if you will the vegetative responses that ultimately go into the regulation of body weight”