ABSTRACT
Regulation of energy homeostasis is critical to the survival of any species. Therefore, intricate behavioral, metabolic, and neuroendocrine mechanisms have evolved to integrate energy intake and dissipation. A delicate balance between intake and expenditure of energy is required to maintain 4healthy weight. Perhaps for teleological reasons, the mechanisms that regulate energy homeostasis are biased in favor of net positive energy and are geared toward defense of weight loss rather than prevention of obesity. Hence, spontaneous weight loss in the absence of disease is rare, and the experience of progressive weight gain in free-living humans is common.
