In support of this notion, genetic ablation of brown and beige fat, for example, by BAT-specific overexpression of the diphtheria toxin or deletion of the central transcription factor, such as euchromatic histone-lysine N-methyltransferase 1 (EHMT1), causes obesity, insulin resistance, glucose intolerance, and dyslipidemia (6, 7). Here, EHMT1 is linked to obesity due to melanocortin 4 receptor deficiency.