Recent literature evidenced that BMI reflects the major influence of genetic variants than epigenetics: in T2D, polymorphisms on the gene FTO (fat mass and obesity-associated), a gene associated with the common forms of obesity [44], IR in T2D [45], modulating insulin activity and BMI [46], seems to be dependent on the diet [47]. The gene discussed is INS; the disease is obesity due to melanocortin 4 receptor deficiency.