Postprandial Glycemic Impact of Meal Timing and Staple Type in Outpatients with Dysglycemia: A Pilot Study Under a Streamlined and Real-World Framework

Objective: Effectively managing postprandial blood glucose is significant for impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM). We developed a streamlined and real-world framework and evaluated how meal timing and staple food type affect postprandial glycemic responses (PPGRs) and the influencing factors on inter-individual differences of PPGR. Materials and methods: We conducted a prospective observational study involving 33 patients with IGT and T2DM. Over a 1-week free-living period, participants completed 7 standardized meal tests: glucose solutions at breakfast, lunch, and dinner; steamed bread, rice, noodles, and oats at lunch. Linear mixed-effects models were used to compare PPGR differences of meal timing and staple food type effects. Linear regression models were applied to explore factors influencing inter-individual heterogeneity in PPGRs. Results: Participants deemed the framework simple and well tolerated. Meal timing had no significant effect on PPGR at 120 minutes (time effect P = 0.110) or 180 minutes (time effect P = 0.097). HOMA-IR was positively associated with the meal timing variability index (adjusted: β = 9.10, 95% CI: 3.01-15.20, P = 0.005). Staple food types affected 120- and 180-minute incremental area under the curve (iAUC), relative peak glucose, and glucose fluctuation amplitude (staple food type effect P < 0.001), but had no significant effects on time to peak or coefficient of variation (staple food type effect P > 0.05). Those born in northern China had a significantly higher refined staple food sensitivity index (adjusted: β = 267.14, 95% CI: 59.18-475.09, P = 0.014). Conclusion: The framework enables convenient, outpatient-based assessment of PPGRs and is highly acceptable to patients. We need to focus not only on the group-level general characteristics of PPGRs but also analyze their individual-level heterogeneity; this emphasizes the critical role of personalized nutrition.