Aims/hypothesis: This secondary analysis compared the effect of a vegan to a portion-controlled diet on insulin use and insulin costs in people with type 1 diabetes (T1D).
Methods: Fifty-eight adults with T1D were randomly assigned to a vegan (n = 29) or a portion-controlled group (n = 29) for 12 weeks. Federal Supply Schedule pharmaceutical pricing was used to assess insulin costs.
Results: Total dose of insulin decreased by 12.1 units/day in the vegan group (p = 0.007), compared to no significant change in the portion-controlled group (treatment effect - 10.7 units/day [95% CI, -21.3 to -0.2]; p = 0.046). Total insulin costs decreased by 27% ($1.08/day; p = 0.003) in the vegan group, compared to no significant change in the portion-controlled group (-$0.38/day [95% CI, -$2.13 to +$1.38]; p = 0.66).
Conclusions/interpretation: This study shows that a low-fat vegan diet could reduce insulin use and insulin costs in people with T1D. Larger trials are needed to confirm these findings.
Trial registration: ClinicalTrials.gov , NCT04944316, registered on June 29, 2021.
Keywords: Diet; Insulin cost; Nutrition; Plant-based; Portion-controlled; Type 1 diabetes; Vegan.
© 2025. The Author(s).