Modulatory effects of ingesting dietary fiber and protein before carbohydrates on postprandial interstitial glucose responses.

Rapid postprandial elevations in interstitial glucose contribute to the progression of type 2 diabetes and associated vascular complications. Nutritional sequencing strategies, such as consuming dietary fiber or protein before carbohydrate intake, have been proposed to attenuate glucose excursions by delaying gastric emptying, stimulating incretin secretion, and enhancing insulin responsiveness. However, observational evidence under real-world conditions remains scarce in both healthy individuals and those with diabetes. We performed an observational study including healthy participants and individuals with type 2 diabetes. All participants were equipped with a continuous glucose monitoring system (FreeStyle Libre™) for 14 days to capture interstitial glucose profiles under daily living conditions. Participants simultaneously recorded dietary intake and meal timing. Postprandial glucose excursions were evaluated by comparing carbohydrate ingestion alone with ingestion preceded by fiber and/or protein. Preceding carbohydrate intake with dietary fiber or protein was associated with significant attenuation of postprandial glucose excursions compared with carbohydrate alone. This effect was particularly evident within the first 120 minutes after eating and was most pronounced when fiber and protein were consumed in combination. Attenuation occurred in both healthy individuals and participants with type 2 diabetes, though the magnitude of suppression varied across groups. Our findings indicate that consuming fiber and protein prior to carbohydrate intake can substantially mitigate rapid postprandial glucose rises. These results support the physiological rationale for macronutrient sequencing and underscore the potential of simple, practical dietary strategies to improve glycemic control in daily life among both healthy individuals and those with diabetes.