Is FUT2 useful for weight loss?

The utility of FUT2 for weight loss is not well-supported by current evidence. FUT2 determines secretor status and influences vitamin B12 absorption and gut microbiome composition. Some observational studies (GWAS) have linked certain FUT2 variants to BMI, but effect sizes are small and not replicated in interventional trials. No robust RCTs demonstrate that tailoring a diet based on FUT2 genotype leads to superior weight loss compared to standard healthy eating. Direct-to-consumer DNA tests may report FUT2 variants, but the clinical actionability for weight management is low. The gene's primary known role is in B12 metabolism and susceptibility to norovirus infection, not directly in energy balance. Therefore, while FUT2 is an interesting candidate, it is not currently a useful or validated target for weight loss interventions. A prudent approach is to focus on overall diet quality and lifestyle rather than single-gene insights.