In 2007, human genome-wide association studies (GWAS) revealed that single nucleotide polymorphisms (SNPs) in the human FTO gene were associated with increased body mass index (BMI) and obesity, which is where the gene and its product derive their full name now: fat mass and obesity-associated (Hinney et al., 2007; Frayling et al., 2007; Scuteri et al., 2007). This evidence concerns the gene FTO and obesity due to melanocortin 4 receptor deficiency.