SH3GLB1 and obesity due to melanocortin 4 receptor deficiency: To assess whether Bif-1 is critical in regulating obesity, we placed WT and Bif-1 KO mice of the C57BL/6 background on a high fat diet (HFD) or a control/standard chow diet (CD) starting at six weeks of age, at which time the mice were indistinguishable by weight.