The FTO (fat mass- and obesity-associated) gene is associated with obesity and diabetes risk in Europeans, Africans, and Asians (22–26), but the minor (obesity-associated) FTO allele is both less common (30–33 vs. 42%) and explains less variation in body mass index (BMI) (0.20 vs. 0.34%) among South Asians compared with Europeans (27, 28). Here, FTO is linked to obesity due to melanocortin 4 receptor deficiency.