Disruption of circadian entrainment of feeding can also contribute to obesity (Hatori et al. 2012; Zarrinpar et al. 2016; Chaix et al. 2019) and, as noted earlier, the disruption of PARP1 leads to changes in the diurnal cycle of feeding and metabolism (Asher et al. 2010; Bai et al. 2011b). Here, PARP1 is linked to obesity due to melanocortin 4 receptor deficiency.