The Effect of a Moderately Restricted Carbohydrate Diet on Cardiometabolic Risk Factors in Overweight and Obese Women With Metabolic Syndrome: A Randomized Controlled Trial

PurposeMetabolic syndrome (MetS) is a major public health concern that increases the risk of cardiovascular disease and mortality. In previous studies of MetS management, low-carbohydrate diets have been strongly emphasized, despite the fact that many apparently healthy individuals have difficulties adhering to these diets on a long-term basis. The purpose of the present study was to elucidate the effects of a moderately restricted carbohydrate diet (MRCD) on cardiometabolic risk factors in women with MetS.MethodsThis parallel 3-month, single-blind randomized controlled trial was conducted in Tehran, Iran, among 70 women with overweight or obesity aged 20 to 50 years with MetS. Patients were randomly allocated to receive either MRCD (42%–45% carbohydrates and 35%–40% fats) (n = 35) or a normal weight loss diet (NWLD) (52%–55% carbohydrates and 25%–30% fats) (n = 35). Both diets contained the same quantity of protein, which accounted for 15% to 17% of total energy. Anthropometric measurements, blood pressure, lipid profile, and glycemic indices were all assessed before and after the intervention.FindingsCompared with the NWLD group, following an MRCD significantly decreased weight (−4.82 vs −2.40 kg; P = 0.01), body mass index (−1.88 vs −0.94 kg/m²; P = 0.01), waist circumference (−5.34 vs −2.75 cm; P = 0.01), hip circumference (−2.58 vs −1.11 cm; P = 0.01), serum triglyceride (−26.8 vs −7.19 mg/dL; P = 0.01), and increased serum HDL-C levels (1.89 vs. 0.24 mg/dL; P = 0.01). There was no significant difference between the 2 diets in waist-to-hip ratio, serum total cholesterol, serum LDL-C, systolic and diastolic blood pressure, fasting blood glucose, insulin levels, or the homeostasis model assessment for insulin resistance.ImplicationsModerate carbohydrate replacement with dietary fats significantly improved weight, body mass index, waist circumference, hip circumference, serum triglyceride, and HDL-C levels among women with MetS. Iranian Registry of Clinical Trials identifier: IRCT20210307050621N1.