Dietary Patterns for Weight and Glycemic Management in Persons With Type 1 Diabetes: A Meta-analysis of Clinical Trials.

Background: Medical nutrition therapy is fundamental for managing glycemia and weight in type 1 diabetes, yet dietary guidance specific to this population and relevant subgroups is lacking.

Purpose: We synthesized the interventional literature investigating diet patterns for glycemic and weight management in youth and adults with type 1 diabetes, with attention to interindividual variation that suggests the need for precision approaches. The protocol was prospectively registered (CRD42024519941).

Data sources: AMED, CINAHL, Cochrane Library, Ovid MEDLINE, Ovid Embase, Google Scholar, and Web of Science Core Collection were searched from January 2011 to June 2024.

Study selection: Clinical trials ≥4 weeks with ≥10 youth and/or adults diagnosed with type 1 diabetes ≥6 months prior and reporting glycated hemoglobin (HbA1c) or weight were included.

Data synthesis: Twelve studies with 668 participants were included. Data were pooled by random-effects models for HbA1c and weight. Studies with insufficient data and subgroup differences were narratively synthesized per Synthesis without meta-analysis guidelines. Pooled results of very low to moderate certainty evidence showed no advantage of any particular diet pattern in randomized trials. Very low-quality evidence from single-arm low carbohydrate trials suggested improved HbA1c over time (-0.63% [95% CI, -0.99 to -0.27]; -6.0 mmol/mol [-10.8 to -3.0]). Wide pooled CIs suggested between-person heterogeneity; however, stratification of results by participant characteristics was rarely performed.

Limitations: Limited evidence precluded subgroup analyses to inform precision nutrition approaches.

Conclusion: Randomized trials are needed to confirm the efficacy of specific diets and determine whether precision nutrition therapies optimize glycemia and weight in persons with type 1 diabetes.