Both cytokines have been demonstrated to promote glucose tolerance, insulin sensitivity, resistance to diet-induced obesity, and upregulated expression of lipolysis and beta-oxidation genes in white and beige fat (Chrysovergis et al., 2014; Chung et al., 2017; Kharitonenkov et al., 2005; Kim et al., 2013; Fisher et al., 2012; Xiong et al., 2017). Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.