LEP and obesity due to melanocortin 4 receptor deficiency: We further crossed bid−/− mice to Ob/Ob mice, which developed the obesity due to lack of leptin and increased food uptake.[27] Male mice with bid deficiency and Ob/Ob genotype gained the same body weight as the Ob/Ob mice (Figure 1C), both of which gained more than WT male mice fed with HFD, suggesting that bid deficiency–induced resistance to obesity was selective toward the effect of diet composition but not the amount of food consumed.