Evidence check: FTO in the context of fatigue

FTO is a gene associated with obesity in GWAS, but with a small effect size (~0.4 kg/m² per risk allele). There is no direct causal evidence linking FTO variants to fatigue. Fatigue may arise secondarily from obesity-related conditions (e.g., sleep apnea), but FTO alone is not a predictor. The evidence for an FTO-fatigue connection is indirect and weak. Lifestyle factors (diet, exercise, sleep) have a much larger impact. MyBody-X tests include FTO, but interpretation should be cautious: no clinical recommendation for fatigue can be derived from FTO. Caveat: population specificity of GWAS results. Source: ENSG00000140718.