Postprandial glycemic control remains a central challenge in the dietary management of gestational diabetes mellitus (GDM). In Pregnancy, a double-blind randomized crossover pilot study evaluated postprandial glycemic responses to meals differing in fat and protein content in individuals with GDM. 

The study enrolled 16 participants with diet-controlled GDM who consumed test meals with similar caloric content ranging from 390 to 411 kilocalories and identical carbohydrate content of 45%, but with either higher fat content at 41% or higher protein content at 35%. Participants were classified as having insulin-resistant or insulin-deficient GDM based on fasting glucose and insulin concentrations. The primary outcome was peak postprandial glucose within three hours following the test meal, measured using continuous glucose monitoring (CGM). Secondary outcomes included glucose area under the curve (AUC) and glycemic excursion, defined as peak postprandial glucose minus pre-meal glucose.

Peak postprandial glucose concentrations were higher following the high-fat meal than the high-protein meal, with mean values of 146.4 mg/dL versus 137.2 mg/dL, respectively (P = 0.03). Glucose AUC was also higher after the high-fat meal compared with the high-protein meal at 26,236 mg/dL·min versus 24,788 mg/dL·min (P = 0.03). Glycemic excursion was similarly greater after the high-fat meal at 68.3 mg/dL compared with 59.7 mg/dL after the high-protein meal (P = 0.03). The difference in peak postprandial glucose between meal types did not differ between insulin-resistant and insulin-deficient GDM.

These findings indicate that, in GDM, protein-enriched meals were associated with lower postprandial glucose levels than fat-enriched meals when total caloric intake and carbohydrate content were equivalent.