Initial evidence suggested that D2R is reduced in obesity (Volkow et al., 2001, 2008; van de Giessen et al., 2013; de Weijer et al., 2014; Kessler et al., 2014) or in response to HFD, even without obesity (van de Giessen et al., 2013), but several studies have failed to replicate this finding (Dunn et al., 2010; Caravaggio et al., 2015; Cosgrove et al., 2015; Tuominen et al., 2015) or found changes in D2R associated with obesity to vary by striatal region (Guo et al., 2014; Adams et al., 2015). Here, DRD2 is linked to obesity due to melanocortin 4 receptor deficiency.