Circadian clocks and eating disorders

Circadian clock function and energy metabolism are tightly interlocked processesand it is a major purpose of the circadian system to ensure an organism's efficient nutrientuptake and processing during the course of the day. Recent studies have provided awealth of information on the role of clocks and clock genes in the regulation of metabolichomeostatic pathways with tissue-specific clocks in the brain and in peripheral organscoordinating the rhythmic activity of key enzymes and regulators of metabolic processesand the associated regulatory signaling pathways. On the other hand, little is still knownabout how circadian clocks affect appetite and food choice. Modern real-time circadianimaging technologies have provided new data on clock gene regulation in metabolismand appetite associated circuits of the central nervous system.Together with large scale genetic association studies these findings support a role forclock genes in linking hedonic and homeostatic regulatory systems of energy metabolism.In this chapter we summarize the current knowledge of circadian clock function inappetite regulation.We describe the neuronal circuits involved, outline circadian aspects of appetiteregulation as well as potential roles for circadian rhythms and sleep in the developmentand therapy of common eating disorders such as anorexia nervosa, bulimia nervosa, bingeand night eating syndromes.