In alignment with previous studies13,15, Mmp14+/− mice exhibited a reduction in body weight and fatty adipose tissue along with reduced loss of lean tissue when they were challenged with a high-fat diet (Supplementary Fig. 2a, b), suggesting that modulation of MT1-MMP activity could reduce the incidence of obesity, a key risk factor in type 2 diabetes. This evidence concerns the gene MMP14 and obesity due to melanocortin 4 receptor deficiency.