Randomization to a Provided Higher-Complex Carbohydrate vs. Conventional Diet in Gestational Diabetes Results in Similar Maternal 24-hour Glycemia and Newborn Adiposity
Objective: Nutrition therapy for gestational diabetes (GDM) has conventionally focused on carbohydrate restriction. In a randomized controlled trial (RCT), we tested the hypothesis that a diet (all meals provided) with liberalized complex carbohydrate (60%) and lower fat (25%)(CHOICE™) could improve maternal insulin resistance and 24-hr glycemia, resulting in reduced newborn adiposity (NB�t; powered outcome) vs. a conventional lower-carbohydrate (40%)/higher fat (45%) diet (LC/CONV).
Research Design and Methods: After diagnosis (~28-30wks), 59 diet-controlled GDM women (mean±SEM; BMI 32±1 kg/m2) were randomized to a provided LC/CONV or CHOICE™ diet (BMI-matched calories) through delivery. At 30-31 and 36-37wks, a 2-hr 75-g OGTT was performed and a continuous glucose monitor (CGM) was worn (72hrs). Cord blood was collected at delivery. NB�t was measured by air displacement plethysmography (13.4±0.4d).
Results: In n=23/group (mean±SEM; LC/CONV [214g/d carbohydrate] vs. CHOICE™ [316g/d]), NB�t (10.1±1 vs. 10.5±1%), birthweight (3303±98 vs 3293±81g), and cord C-peptide were not different. Weight gain, physical activity, and gestational age at delivery were similar. At 36-37wks, CGM fasting (86±3 vs. 90±3), 1-hr (119±3 vs.117±3), 2-hr postprandial (106±3 vs.108±3mg/dL), %time-in-range (TIR 92±1 vs. 91±1%), and 24-hr glucose area-under-the curve (AUC) were similar between diets. The %time >120mg/dL was statistically higher (8%) in CHOICE™ as was the nocturnal glucose AUC; however, nocturnal %TIR (63-100mg/dL) was not different. There were no between-group differences in OGTT glucose and insulin at 36-37wks.
Conclusion: A ~100g/d difference in carbohydrate intake did not result in between-group differences in NB�t, cord C-peptide, maternal 24-hr glycemia, %TIR, or insulin resistance indices in diet-controlled GDM.