What does a FTO genotype mean for lifestyle?

The FTO gene variant (e.g., rs9939609) is the most well-studied common genetic risk factor for obesity. Carriers of the risk allele (A) have a slightly higher average BMI and increased risk of overweight – the effect is modest (about 1–3 kg body weight) and heavily influenced by lifestyle. Importantly, FTO is not a 'destiny gene'. Studies indicate that physical activity can partially offset the genetic disadvantage. No specific 'FTO diet' is evidence-based; general recommendations for balanced nutrition and exercise apply to all genotypes. The test provides a risk indication, not a diagnosis. Communication should emphasize that lifestyle interventions are effective and risk is not deterministic. Beware of exaggerated marketing claims promoting personalized nutrition based solely on FTO. The evidence is human-strong (GWAS, meta-analyses), but the clinical relevance for an individual remains limited.