BACKGROUND/OBJECTIVES: The prevalence of metabolic syndrome (MetS) and obesity has increased worldwide, as well as in Taiwan, particularly in women aged>40 years. The purpose of this study was to elucidate the effects of a calorie-restriction diet (CR) supplemented with protein and n-3 polyunsaturated fatty acids (PUFAs) on women with MetS. SUBJECTS/METHODS: A total of 143 eligible female participants were recruited and assigned to four dietary interventions such as 1500-kcal CR, calorie-restriction meal-replacement diet (CRMR), calorie-restriction diet with fish oil supplementation (CRF) and calorie-restriction meal-replacement diet with fish oil supplementation (CRMRF). The changes in anthropometric measures, metabolic profiles, inflammatory response and the Z-score of severity of MetS were evaluated. RESULTS: Among 143 female MetS patients enrolled, 136 patients completed the 12-week study. After the 12-week dietary interventions, we observed reductions in body weight (BW), body mass index (BMI) and waist circumference (WC) in all groups. BMI and triglyceride (TG) levels decreased significantly in the CRMR, CRF and CRMRF groups, but not in the CR group. The homeostasis model assessment of insulin resistance (HOMA-IR) had significantly improved in all four groups, and the levels of interleukin-6 (IL-6) and C-reactive protein (CRP) had significantly decreased in the CRF and CRMRF groups. Following the interventions, the changes in waist circumference (WC), mean arterial pressure (MAP), fasting blood glucose (FBG), TGs, HOMA-IR, CRP and IL-6 significantly correlated with the reductions in Z-score of MetS severity. CONCLUSIONS: Our study results indicate that a calorie-restriction dietary intervention combined with various macronutrients can reduce the severity of MetS in women and increase recovery from MetS by almost twofold in comparison with a CR alone.