UCP1 and obesity due to melanocortin 4 receptor deficiency: In rodent models of obesity, the activation of BAT and uncoupling protein (UCP1)-positive beige adipocytes in white adipose tissue (WAT) by cold exposure and sympathomimetics (i.e., β3-agonists) can attenuate or reverse obesity, diabetes and atherosclerosis, thus improving metabolic health [1].