A Healthy, Low-Carbohydrate Diet during Pregnancy Is Associated with a Reduced Risk of Gestational Diabetes Mellitus

Abstract

Context: Evidence on the associations of low-carbohydrate diet (LCD) during pregnancy with gestational diabetes mellitus (GDM) has been limited and inconsistent. Objective: We aimed to prospectively evaluate the risk of GDM associated with the LCD considering the quality of macronutrients. Methods: All participants were from a prospective cohort in Wuhan, China. The overall, healthy LCD (emphasizing low-quality carbohydrates, plant protein, and unsaturated fat), and unhealthy LCD (emphasizing high-quality carbohydrates, animal protein, and saturated fat) scores were calculated according to the percentage of energy intake from carbohydrates, protein, and fat. GDM was screened by a 75-g oral glucose tolerance test between 24 and 28 weeks. Poisson regression models were used to calculate relative risks (RRs) and 95% CIs. Results: Of 2337 pregnant women, 257 (11.0%) were diagnosed with GDM. Overall LCD score was not associated with risk of GDM, but the healthy and unhealthy LCD scores were associated with the risk of GDM. The multivariable-adjusted RRs (95% CI) were 0.68 (0.49-0.94) and 1.52 (1.11-2.08) for healthy and unhealthy LCD scores comparing the highest with the lowest quartile. Substituting high-quality carbohydrates for low-quality carbohydrates and animal protein, and substituting unsaturated fat for saturated fat, were associated with a 13% to 29% lower risk of GDM. Conclusion: A healthy LCD during pregnancy characterized by high-quality carbohydrates, plant protein, and unsaturated fat was associated with a lower risk of GDM, whereas an unhealthy LCD consisting of low-quality carbohydrates, animal protein, and saturated fat was associated with a higher risk of GDM.