In an observational prospective cohort design from the RCT, Prevención con Dieta Mediterránea (PREDIMED), the investigators concluded that genetic predisposition to type 2 diabetes associated with the Transcription Factor 7-Like 2 Gene [TCF7L2 gene (rs790314 TT)] homozygosity could be counteracted through precision nutrition interventions with the Mediterranean diet [55]. The gene discussed is TCF7L2; the disease is type 2 diabetes mellitus.