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Recent advances of neuroscience shed a light in the neural pathway and mechanisms for food intake regulation. The central nervous system(CNS)has also been recognized as a crucial organ to regulate metabolism in peripheral tissues. This includes the increase in glucose and fatty acid utilization in skeletal muscle as well as in brown adipose tissue and the heart, improving type 1 diabetes without change in insulin secretion. CNS regulation for food intake and energy metabolism is important to understand the mechanism for homeostatic regulation in living body.

Feeding behavior is regulated by homeostatic and hedonic mechanisms. NPY/AgRP neurons in the arcuate hypothalamus are involved in the homeostatic regulation, and dopaminergic neurons in the ventral tegmental area regulating the nucleus of accumbens are involved in the hedonic regulation, respectively. Food preference also appears to be regulated by both homeostatic and hedonic mechanisms. However, molecular mechanism for food preference regulation remains elusive and further studies are necessary.

Food intake is precisely regulated in all normal individuals, with a variation of <1%. The hypothalamus is a critical component of the forebrain pathways that regulate long-term energy homeostasis, and it plays a particularly important role in integrating hormonal, neurotransmitter, and nutrient signals. Obese animals fed with high-fat diets show an increase in the inflammatory signals, endoplasmic reticulum stress, and radical oxygen species in the hypothalamus and impairment in the systems regulating food intake. AMP kinase (AMP-activated protein kinase [AMPK]) is a "metabolic sensor" present in a wide variety of organisms, from yeast to mammals. Recent studies have indicated the role of AMPK in hypothalamic neurons in the integration of hormonal, neurotransmitter, and nutrient signals. Furthermore, analysis of genetically engineered mice has revealed that AMPK alters the fatty acid metabolism in the hypothalamic neurons as well as in peripheral tissues, and thereby regulates feeding behavior. Thus, hypothalamic neurons and intracellular signaling pathway that includes AMPK-fatty acid metabolism appear to be the critical components that regulate food intake and body weight.