CLOCK and metabolic disease: Several studies have shown a close relationship between the circadian clock system and nutrient metabolism; thus, it is widely established that circadian clock disruptions result in metabolic disorders and ultimately obesity and the related diseases (Rudic et al. 2004, Broberger 2005, Turek et al. 2005, Buijs & Kreier 2006, Oishi et al. 2006, Kennaway et al. 2007, Lamia et al. 2008, Yang et al. 2009, Shimba et al. 2011).