UCP1 and obesity due to melanocortin 4 receptor deficiency: Thus, the mere presence of high amounts of UCP1 and highly recruited brown and brite/beige adipose tissues does not ensure protection against obesity, and the obese state observed in high-fat/high-sugar-fed mice should not be understood as the passive outcome of overeating but as a condition actively strived for by the metabolic control systems of the mice under these exact conditions.