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 a-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 (27·8 v. 26·0 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. The metabolic syndrome is a cluster of interrelated and modifiable risk factors for CVD including abdominal obesity, hypertension, dyslipidaemia and hyperglycaemia (1) . Diet is the cornerstone in the prevention and therapy of this metabolic disorder, with long-term weight reduction accompanied by an improvement in the metabolic risk profile as the primary therapeutic goal for obese patients. There is general agreement that a high intake of SFA and trans-fatty acids should be considerably reduced, because they increase LDL-cholesterol levels, impair insulin sensitivity and represent a dietary pattern with high energy density (ED), and therefore promote hyperenergetic diets (2 -5) . However, it is still a matter of debate whether saturated and hydrogenated fat should be replaced preferentially by carbohydrates or monounsaturated fat in these patients.For decades, low-fat, high-carbohydrate diets have been recommended as the most suitable approach for weight reduction with the focus on a high proportion of carbohydrates rather than on their physiological quality (6,7) . However, there is now evidence that the carbohydrate quality is more decisive than its quantity. A high intake of refined carbohydrates with a high glycaemic index has not only detrimental effects on the metabolic risk profile by raising serum glucose and TAG levels and decreasing , but is also positively associated with an elevated ED (4) , and therefore cannot be recommended for weight reduction. On the other hand, a high intake of fi...