Overweight and diabetes increase risk of cardiovascular disease but the mechanism(s) that account for this effect remain to be clarified. Oxidation of low-density lipoprotein (LDL) is thought to contribute to atherosclerosis. Diabetes may increase oxidative stress, and this may contribute to increased risk of cardiovascular disease in diabetics. Caloric restriction and the initiation of exercise may increase oxidative stress in the short term and may thus adversely affect cardiovascular disease. Over the long term, metabolic adaptation may reduce oxidative stress. Such adaptation, together with beneficial changes in lipoprotein concentration, composition, and character, may allow expression of beneficial effects of weight loss on cardiovascular endpoints. However, the influence of weight loss on measures of lipoprotein oxidation/oxidative stress and antioxidant status in overweight diabetics has never been investigated.