 Our primary hypothesis states: A significant and biologically relevant proportion of the individual variation in changes in the plasma metabolome in response to dietary saturated fat and prebiotic intake will be due to APOA2265TC genotypes. Specifically, subjects homozygous CC for the less common C allele will respond to decreases in total dietary saturated fat and increases in prebiotics i.e., plant-based diet with significantly greater improvement of metabolites related to gut health, inflammation and other cardiometabolic traits than subjects homozygous TT for the common T allele. 