The regulation of
body weight is a complex process which relies on a balance between supply of nutrients and demand on these nutrients in the form of energy expenditure. Various central and peripheral mechanisms play a crucial role in maintaining this balance. While various
neuropeptides in the central nervous system (CNS), particularly in the hypothalamus, maintain the necessary harmony between
hyperphagia and
anorexia, peripheral signals arising from the gastrointestinal tract (
cholecystokinin-8 [CCK-8],
amylin), pancreas (
insulin) and adipose tissue (
leptin) provide the necessary stimuli or a feedback inhibition for the synthesis and secretion of these hypothalamic
neuropeptides. Various metabolites of the
carbohydrate and fat metabolism are also involved in regulating the neuronal activity in the hypothalamus which ultimately leads to a release of key
neuropeptides. In addition to the central mechanisms, peripheral mechanisms that regulate energy expenditure, particularly in the brown adipose tissue and skeletal muscle, are critical in maintaining the overall balance. Insight into these mechanisms sets the stage for developing novel strategies in the treatment of emerging childhood diseases such as
obesity,
anorexia nervosa, and
bulimia. Further, delineation of these processes in the fetus and newborn sets the stage for investigating their role in molding the adult phenotype due to intrauterine adaptations.