One year follow-up after a randomized controlled trial of a 130 g/day low-carbohydrate diet in patients with type 2 diabetes mellitus and poor glycemic control.

BACKGROUND & AIMS: Recently, we conducted a prospective randomized controlled trial (RCT) showing that a 6-month 130g/day low-carbohydrate diet (LCD) reduced HbA1c and BMI more than a calorie restricted diet (CRD). [1] To assess whether the benefits of the LCD persisted after the intensive intervention, we compared HbA1c and BMI between the LCD and CRD groups at 1 year after the end of the 6-month RCT. METHODS: Following the end of the 6-month RCT, patients were allowed to manage their own diets with periodic outpatient visits. One year later, we analyzed clinical and nutrition data. RESULTS: Of the 66 participants in the original study, 27 in the CRD group and 22 in the LCD group completed this trial. One year after the end of the original RCT, the carbohydrate intake was comparable between the groups (215 [189-243]/day in the CRD group and 214 (176-262) g/day in the LCD group). Compared with the baseline data, HbA1c and BMI were decreased in both groups (CRD: HbA1c -0.4 [-0.9 to 0.3] % and BMI -0.63 [-1.20 to 0.18] kg/m2; LCD: HbA1c -0.35 [-1.0 to 0.35] % and BMI -0.77 [-1.15 to -0.12] kg/m2). There were no significant differences in HbA1c and BMI between the groups. CONCLUSIONS: One year after the diet therapy intervention, the beneficial effect of the LCD on reduction of HbA1c and BMI did not persist in comparison with CRD. However, combining the data of both groups, significant improvements in HbA1c and BMI from baseline were observed. Although the superiority of the LCD disappeared 1 year after the intensive intervention, these data suggest that well-constructed nutrition therapy programs, both CRD and LCD, were equally effective in improving HbA1c for at least 1 year. TRIAL REGISTRATION: University Hospital Medical Information Network (UMIN) ID000010663.

A randomized controlled trial of 130 g/day low-carbohydrate diet in type 2 diabetes with poor glycemic control.

BACKGROUND & AIMS: The usefulness of low-carbohydrate diet (LCD) for Japanese patients with type 2 diabetes mellitus (T2DM) has not been fully investigated. Therefore, we compared the effectiveness and safety of LCD with calorie restricted diet (CRD). METHODS: This prospective, randomized, open-label, comparative study included 66 T2DM patients with HbA1c >7.5% even after receiving repeated education programs on CRD. They were randomly allocated to either the 130g/day LCD group (n = 33) or CRD group (n = 33). Patients received personal nutrition education of CRD or LCD for 30 min at baseline, 1, 2, 4, and 6 months. Patients of the CRD group were advised to maintain the intake of calories and balance of macronutrients (28× ideal body weight calories per day). Patients of the LCD group were advised to maintain the intake of 130 g/day carbohydrate without other specific restrictions. Several parameters were assessed at baseline and 6 months after each intervention. The primary endpoint was a change in HbA1c level from baseline to the end of the study. RESULTS: At baseline, BMI and HbA1c were 26.5 (24.6-30.1) and 8.3 (8.0-9.3), and 26.7 (25.0-30.0) kg/m2 and 8.0 (7.6-8.9) %, in the CRD and LCD, respectively. At the end of the study, HbA1c decreased by -0.65 (-1.53 to -0.10) % in the LCD group, compared with 0.00 (-0.68 to 0.40) % in the CRD group (p < 0.01). Also, the decrease in BMI in the LCD group [-0.58 (-1.51 to -0.16) kg/m2] exceeded that observed in the CRD group (p = 0.03). CONCLUSIONS: Our study demonstrated that 6-month 130 g/day LCD reduced HbA1c and BMI in poorly controlled Japanese patients with T2DM. LCD is a potentially useful nutrition therapy for Japanese patients who cannot adhere to CRD. This trial was registered at http://www.umin.ac.jp/english/ (University Hospital Medical Information Network: study ID number 000010663).