What role does FTO play in Sport?

FTO (fat mass and obesity-associated) is a gene whose variants (especially rs9939609) are strongly linked to body fat percentage, BMI, and obesity risk. In sports, FTO plays an indirect role: higher BMI can impair performance in weight-dependent disciplines (e.g., endurance running, jumping), while in strength sports higher fat mass may not be detrimental. Direct effects on muscle metabolism or training adaptation are not clearly established; evidence comes mainly from population GWAS, not controlled sport interventions. Moreover, individual SNP effects are small and overshadowed by lifestyle factors. Therefore, a DNA test for FTO variants cannot predict sport-specific aptitude. In practice, FTO is not a 'sport gene' but an obesity risk factor that may influence performance indirectly via body weight. Training or nutrition strategies should not be based solely on FTO.