Besides the well known plastic process of beiging, diet-induced obesity in mice evokes vascular remodeling and functional hypoxia leading to a “whitening” phenotype in BAT, characterized by mitochondrial dysfunction and loss, lipid droplet accumulation, and decreased expression of Ucp1 and Vascular endothelial growth factor, and tissue inflammation (33–36). Here, UCP1 is linked to obesity due to melanocortin 4 receptor deficiency.