What role does ACTN3 play in Abnehmen?

ACTN3 encodes alpha-actinin-3, a structural protein in fast-twitch (type II) muscle fibers. A common loss-of-function variant (R577X) results in complete ACTN3 deficiency in about 18 % of Europeans. This deficiency is associated with reduced sprint and power performance, but not directly with weight loss (Abnehmen). Evidence for a role in weight management is weak: some studies suggest a slightly higher resting energy expenditure in ACTN3-deficient individuals, while others find no effect. Weight loss is primarily driven by calorie balance, macronutrient composition, and physical activity – not by single gene variants. ACTN3 testing in consumer genetics is therefore not clinically relevant for weight loss. Evidence level: human-moderate for athletic performance, but unclear for weight loss. Source: GWAS studies (e.g., PMID 23335917) link ACTN3 to sprint performance, not weight regulation.