As mentioned previously, the discovery of leptin represents a huge step in the study of obesity. Adipose tissue, until then considered as inert and metabolically inactive, is now regarded to be capable of producing proteins with autocrine, paracrine, and endocrine activity. Further discovery have shown that various adipokines, such as adiponectin, visfatin, resistin are produced in adipose tissue and involved in the pathophysiology of obesity [57]. Recent studies show that many genes in adipose tissue show circadian rhythmicity [58]. Microarrays carried out in animals and humans have shown that approximately 7 to 21% of active genes expressed in white and brown adipose tissue follow a daily rhythmic pattern [59]. Indeed, adipose tissue has been seen to express clock genes with a circadian rhythmicity, which is capable of triggering this tissue and even of modulating other genes, the so-called Clock control genes [60]. Circadian oscillators play an indispensable role in the coordination of physiological processes with the cyclic changes in the physical environment. A significant number of recent clinical and molecular studies suggest that circadian biology may play an important role
