Barres et al. showed that promoter methylation of peroxisome proliferator-activated receptor gamma coactivator-1αlpha (PPARGC1A) and pyruvate dehydrogenase kinase isozyme-4 (PDK4) were altered with obesity and were restored to non-obese levels after RYGB induced weight loss16. This evidence concerns the gene PDK4 and obesity due to melanocortin 4 receptor deficiency.