Effects of a six-month low-carbohydrate diet on glycemic control, body composition and cardiovascular risk factors in patients with type 2 diabetes: an open-label RCT

Aims To investigate the efficacy and safety of a non-calorie-restricted low-carbohydrate diet (LCD) on glycemic control, body composition, and cardiovascular risk factors in patients with type 2 diabetes (T2D) instructed to maintain their non-insulin antidiabetic medication and physical activity. Material and methods In an open-label RCT, patients with T2D were randomized 2:1 to either a LCD with a maximum of 20 E% from carbohydrates (n=49) or a control diet with 50-60 E% from carbohydrates (n=22) for 6 months. Examinations at enrollment and after 3 and 6 months included blood sample analyses, anthropometrics, blood pressure, accelerometer-based assessment of physical activity and food diaries. Total fat mass and lean mass were determined by DXA-scan. The mean-difference in change between groups from baseline are reported. Results The LCD group decreased carbohydrate intake to 13.4 E% and increased fat intake to 63.2%, which was -30.5±2.2 E% lower for carbohydrates and 30.6±2.2 E% higher for fat, respectively, compared with the control group (all p<0.001). The LCD reduced HbA1c after 3 months (-8.9±1.7 mmol/mol; p<0.0001), and this was maintained after 6 months (-7.5±1.8 mmol/mol; p<0.0001) compared with the control diet. The LCD also reduced weight (-3.9±1.0 kg), BMI (-1.4±0.4 kg/m2) and waist (-4.9±1.3 cm) compared to control diet (all p