Recently, we and others demonstrated that serum and skeletal levels of DKK1, but not SOST, are elevated in obese mice20, 30 and in patients with type 2 diabetes mellitus.31, 32, 33 As DKK1 is a potent suppressor of bone formation and bone mass,34, 35, 36 we hypothesized that elevated DKK1 levels may drive obesity‐induced bone loss in mice. This evidence concerns the gene SOST and obesity due to melanocortin 4 receptor deficiency.