One study reported that carriers of the A allele for an SNP (rs10423928) within GIPR, a candidate gene chosen based on the hypothesis that it encodes the receptor for the incretin hormone gastric inhibitory polypeptide (41), had a lower 12-y incidence of T2D only if they also consumed a diet higher in fat or lower in carbohydrate (41). This evidence concerns the gene GIPR and type 2 diabetes mellitus.