In therapy of the metabolic syndrome, the optimal dietary approach with regard to its macronutrient composition and metabolically favourable food components, such as the plant-derived n-3 fatty acid α-linolenic acid (ALA), is still a matter of debate. We investigated the effects of a hypoenergetic diet with low energy density (ED) enriched in rapeseed oil, resulting in high MUFA content and an ALA intake of 3.5 g/d on body weight and cardiovascular risk profile in eighty-one patients with the metabolic syndrome in comparison with an olive oil diet rich in MUFA, but with a low ALA content. After a 6-month dietary intervention, body weight was significantly reduced in the rapeseed oil and olive oil groups ( -7.8 v. -6.0 kg; P < 0.05). There were significant decreases in systolic blood pressure, total cholesterol and LDL-cholesterol, and insulin levels in both groups (P < 0.05). For all of these changes, no inter-group differences were observed. After the rapeseed oil diet, diastolic blood pressure declined more than after the olive oil diet (P < 0.05 for time × group interaction). Furthermore, concentrations of serum TAG were significantly reduced after the high ALA intake, but not in the low ALA group (P < 0.05 for time × group interaction). In conclusion, our dietary food pattern with a low ED and high intakes of MUFA and ALA may be a practical approach for long-term dietary treatment in patients with the metabolic syndrome, leading to weight reduction and an improvement in the overall cardiovascular risk profile.