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. 2025 Jun 17;110(7):1828-1835.
doi: 10.1210/clinem/dgae725.

The Role of Whole Food Plant-Based Food Intake on Postprandial Glycemia in Type 1 Diabetes

Rebecca J Johnson  1 , Simon Bergford  2 , Robin L Gal  2 , Peter Calhoun  2 , Karissa Neubig  3 , Corby K Martin  3 , Michael C Riddell  4 , Ananta Addala  1   5
Affiliations

The Role of Whole Food Plant-Based Food Intake on Postprandial Glycemia in Type 1 Diabetes

Rebecca J Johnson et al. J Clin Endocrinol Metab. .

Abstract

Context: A whole food plant-based diet (WFPBD), minimally processed foods with limited consumption of animal products, is associated with improved health outcomes. The benefits of WFPBD are underexplored in individuals with type 1 diabetes (T1D).

Objective: The primary objective of this analysis is to evaluate the association between WFPBD on glycemia in individuals with T1D.

Methods: Utilizing prospectively collected meal events from the Type 1 Diabetes Exercise Initiative, we examined the effect of WFPBD intake on glycemia, determined by the plant-based diet index (PDI). The PDI calculates overall, healthful (hPDI), and unhealthy PDI (uPDI) to evaluate for degree of processed foods and animal products (ie, WFPBD). Mixed effects linear regression model assessed time in range (TIR), time above range, and time below range.

Results: We analyzed 7938 meals from 367 participants. TIR improved with increasing hPDI scores, conferring a 4% improvement in TIR between highest and lowest hPDI scores (high hPDI: 75%, low hPDI: 71%; P < .001). Compared with meals with low hPDI, meals with high hPDI had lower glucose excursion (high hPDI: 53 mg/dL, low hPDI: 62 mg/dL; P < .001) and less time >250 mg/dL (high hPDI: 8%, low hPDI: 14%; P < .001). These effects were present but less pronounced by PDI (high PDI: 74%, low PDI: 71%; P = .01). No differences in time below 70 mg/dL and 54 mg/dL were observed by PDI or hPDI.

Conclusion: Meal events with higher hPDI were associated with 4% postprandial TIR improvement. These benefits were seen primarily in WFPBD meals (captured by hPDI) and less pronounced plant-based meals (captured by PDI), emphasizing the benefit of increasing unprocessed food intake over limiting animal products alone.

Keywords: nutrition; obesity; plant-based diet; time in range; type 1 diabetes; whole foods.

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Figures

Figure 1.
Figure 1.
Adjusted % time in range by PDI score.
Figure 2.
Figure 2.
Adjusted excursion by PDI score.
See this image and copyright information in PMC

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