Legume intake could specifically protect against lipid peroxidation in addition to the effects associated to weight loss when included in hypocaloric diets. Thus, 30 obese subjects ( age: 36 +/- 8 years and BMI: 32.0 +/- 5.3 kg/m(2)) were nutritionally treated by a 8-week energy restriction ( -30% energy expenditure) with a legume enriched diet ( 4 days/week servings, n = 15) or without legumes ( control diet ( CD), n = 15). Body weight, circulating cholesterol, oxidized LDL ( ox-LDL), malondialdehyde ( MDA) and urinary 8-isoprostane F-2 alpha ( 8-iso-PGF(2 alpha)) were measured at baseline and at endpoint. After the nutritional intervention, all obese subjects lost weight, specially those individuals who followed the legumes-enriched diet as compared to the CD ( -7.7 +/- 3 vs. - 5.3 +/- 2.7%; p = 0.023), which was accompanied by marked decreases in total cholesterol levels ( p < 0.001) and statistically significant diet-related reductions on plasma ox-LDL, plasma MDA and urinary 8-iso-PGF(2 alpha) output. Therefore, a balanced diet with moderate caloric restriction including 4 day/week legume servings empowered the oxidative stress improvement related to weight loss through a reduction in lipid peroxidation as compared to a control hypocaloric diet.