Taking into account the paucity of studies investigating the in vivo antioxidant potential of olive oils rich in OO and the dependence of platelet activity on the redox potential, this study aims to investigate the impact of five meals differing in the lipid source on the postprandial levels of TBARS, glutathione peroxidase activity in serum (GPx3) and erythrocytes (GPx1), and protein carbonyls in serum of T2DM patients. Here, GPX1 is linked to type 2 diabetes mellitus.