Could the timing of the first daily meal influence glucose patterns in gestational diabetes? A secondary analysis published in Diabetologia assessed whether earlier morning eating relates to 24-hour glucose profiles in pregnancies affected by gestational diabetes mellitus (GDM).
The analysis included 71 pregnant individuals with GDM from a randomized study of self-capillary blood glucose (SCBG) monitoring with or without additional real-time continuous glucose monitoring (CGM). Participants were included if postprandial SCBG values were available to infer meal timing. Based on the median time of the first meal, the cohort was divided into early eating (before 09:56 hours) and late eating (after 09:56 hours) groups. The 24-hour CGM profiles were compared using cosinor and linear analyses adjusted for maternal age, gestational age, medication use, and primary study group assignment.
Over 24 hours, glucose concentrations increased during the day and decreased during the night. This rhythm occurred earlier in the early-eating group. Cosinor analysis showed significant time-of-day effects for the 24-hour component (−0.32 mmol/L/min, p < 0.001) and 12-hour component (−0.11 mmol/L/min, p < 0.001). Significant group × time-of-day effects were also observed for the 24-hour component (0.09 mmol/L/min, p < 0.001) and 12-hour component (0.04 mmol/L/min, p < 0.001).
During daytime hours, glucose trajectories showed a significant time-of-day effect (7.0 × 10⁻⁴ mmol/L/min, p < 0.001) and group × time-of-day effect (7.0 × 10⁻⁵ mmol/L/min, p<0.001), but no overall group effect (0.01 mmol/L, p=0.950). Overnight, glucose decreased in both groups by approximately 0.67 ± 0.39 mmol/L.
However, the late-eating group had higher nocturnal glucose by 0.26 mmol/L than the early-eating group (p = 0.023). Overnight analysis also showed a significant time-of-day effect (−0.09 mmol/L/min, p < 0.001) and group × time-of-day effect (−0.01 mmol/L/min, p < 0.001). These results suggest that meal timing, with emphasis on earlier eating patterns, may improve nocturnal interstitial glucose in GDM.
