Importantly, BAT‐Mfn2‐KO mice fed a chow diet did not show differences in glucose tolerance (Figs 4A and EV2C), demonstrating that metabolic improvement is a consequence of resistance to diet‐induced obesity and/or requires the component of HFD stimulating an adrenergic response in BAT 10. This evidence concerns the gene MFN2 and obesity due to melanocortin 4 receptor deficiency.