J. Feeley, A. Abraham, N. Gonzalez, R. Parab, L. Chadalawada and FJ. Pasquel (2026). Dietary approaches for glycemic management in type 1 diabetes: A systematic review of Mediterranean and low-carbohydrate diets. Primary care diabetes. https://doi.org/10.1016/j.pcd.2026.06.004

PubMed 42414108

[Abstract]
BACKGROUND/OBJECTIVES: Specific dietary approaches for better management of type 1 diabetes (T1D) have not been thoroughly investigated. We conducted a systematic review to evaluate the Mediterranean and low-carbohydrate diets for glycemic management in people with T1D.

METHODS: We examined longitudinal studies (cohort studies and clinical trials) including individuals with T1D who followed low-carbohydrate diets (<26% calories from carbohydrates and/or <130 g of carbohydrates per day) and/or a Mediterranean diet, while hemoglobin A1c (HbA1c) and/or time in range (TIR) were measured. Additional eligibility criteria included publication in English and availability of a full-text primary research article. Non-longitudinal studies, abstracts, and studies published in languages other than English were excluded. Results were synthesized narratively, and the GRADEpro Guideline Development Tool was used to assess article quality.

RESULTS: A total of 565 studies were identified from PubMed, the Web of Science, and citation chasing. After removal of duplicates and further evaluation, 22 studies (6 cohort studies and 16 clinical trials; total n = 3284) were included in this review. The search was initially completed in May 2024, and updated February 2026. Low-carbohydrate diets were associated with better glycemic management when compared to usual diets or baseline glycemic parameters. Studies using CGM were overall underpowered. The impact of Mediterranean diets was less clear, but generally appeared to be less effective at improving glycemic management than low-carbohydrate diets.

DISCUSSION: Although structured dietary interventions for T1D hold promise for improving glycemic outcomes, further research is needed to determine exactly which dietary intervention is most beneficial for this population. The evidence provided by included studies is limited by small sample sizes and short durations; better powered, longer-term studies are required to inform clinical recommendations.