Some regulators of transcription such as PR/SET Domain 16 (PRDM16, a transcriptional coregulator that controls the development of brown adipocytes in BAT), and peroxisome proliferator-activated receptor gamma (PPARγ), hormones such as irisin and fibroblast growth factor 21 (FGF21) and chemical compounds such as thiazolidinediones (TZDs) were reported to induce WAT browning, increase energy expenditure, and protect mice from diet-induced obesity (Seale et al., 2011; Boström et al., 2012; Fisher et al., 2012; Ohno et al., 2012; Cohen et al., 2014). This evidence concerns the gene FGF21 and obesity due to melanocortin 4 receptor deficiency.