In a recent comprehensive study (Anderson et al., 2018), we reported that a carnosine analog which is resistant to degradation by carnosinase can mitigate insulin resistance and liver steatosis/fibrosis in diet induced obesity, even in mice with enhanced lipid peroxidation due to GPx4 haploinsufficiency (i.e., GPx4+/− mice). The gene discussed is GPX4; the disease is obesity due to melanocortin 4 receptor deficiency.