A randomized controlled trial investigating the effects of a low-glycemic index diet on pregnancy outcomes in gestational diabetes mellitus
OBJECTIVE: The prevalence of gestational diabetes mellitus (GDM) is rising. There is little evidence to demonstrate the effectiveness of one dietary therapy over another. We aimed to investigate the effect of a low-glycemic index (LGI) versus a conventional high-fiber diet on pregnancy outcomes, neonatal anthropometry, and maternal metabolic profile in GDM.RESEARCH DESIGN AND METHODS: Ninety-nine women (age 26-42 years; mean ÃÂ± SD prepregnancy BMI 24 ÃÂ± 5 kg/mÃÂ²) diagnosed with GDM at 20-32 weeks' gestation were randomized to follow either an LGI (n = 50; target glycemic index [GI] ~50) or a high-fiber moderate-GI diet (HF) (n = 49; target GI ~60). Dietary intake was assessed by 3-day food records. Pregnancy outcomes were collected from medical records.RESULTS: The LGI group achieved a modestly lower GI than the HF group (mean ÃÂ± SEM 47 ÃÂ± 1 vs. 53 ÃÂ± 1; P < 0.001). At birth, there was no significant difference in birth weight (LGI 3.3 ÃÂ± 0.1 kg vs. HF 3.3 ÃÂ± 0.1 kg; P = 0.619), birth weight centile (LGI 52.5 ÃÂ± 4.3 vs. HF 52.2 ÃÂ± 4.0; P = 0.969), prevalence of macrosomia (LGI 2.1% vs. HF 6.7%; P = 0.157), insulin treatment (LGI 53% vs. HF 65%; P = 0.251), or adverse pregnancy outcomes.CONCLUSIONS: In intensively monitored women with GDM, an LGI diet and a conventional HF diet produce similar pregnancy outcomes.