This randomized crossover clinical trial was performed with 30 overweight or obese (body mass index [BMI] > 25 kg/m2) women with MetS. After a 2-wk run-in period, participants were randomly assigned to consume either a calorie-restricted high-carbohydrate (HC) diet (60%-65% of energy from carbohydrates and 20%-25% from fats) or a calorie-restricted moderately restricted carbohydrate (MRC) diet (43%-47% of total calories as carbohydrate and 36%-40% as dietary fats) for 6 wk. Protein contents of both diets were 15% to 17% of total energy. A 2-wk washout period was applied following which participants were crossed over to the alternate treatment arm for an additional 6 wk. Anthropometric, blood pressure, and biochemical measurements were performed before and after each phase of intervention.
Mean age and BMI of study participants was 42.4 y and 33 kg/m2, respectively. A trend toward greater reduction in waist (鈭?.9 versus 鈭?.6 cm; P = 0.07) and hip circumferences (鈭?.7 versus 鈭?.5 cm; P = 0.07) as well as serum triglyceride (TG) levels (鈭?1.3 versus 0.13 mg/dL; P = 0.07) was observed after consumption of an MRC diet compared with an HC diet. The TG to high-density lipoprotein cholesterol (HDL-C) ratio had a tendency to improve with the MRC diet rather than the HC diet (鈭?.9 versus 鈭?.1; P = 0.06). Consumption of the MRC diet resulted in a greater reduction of systolic blood pressure (鈭?.93 versus 鈭?.97 mm Hg; P = 0.06) and diastolic blood pressure (鈭?2.7 versus 鈭?.77 mm Hg; P = 0.001) compared with the HC diet. The prevalence of MetS was significantly decreased following the consumption of the MRC diet (P = 0.03). The two diets were not significantly different in terms of their effect on fasting plasma glucose, serum HDL-C, low-density lipoprotein cholesterol, and total cholesterol, insulin levels, and Homeostasis Model Assessment-Insulin Resistance.
Moderate replacement of carbohydrates by dietary fats was not associated with statistically different changes in fasting plasma glucose, insulin, or atherogenic dyslipidemia among individuals with the metabolic syndrome; however, it resulted in decreased diastolic blood pressure and lower prevalence of the metabolic syndrome.