Diet behavior change techniques in type 2 diabetes: A systematic review and meta-analysis

Objective: Dietary behavior is closely connected to type 2 diabetes. The purpose of this metaanalysis was to identify behavior change techniques (BCTs) and specific components of dietary interventions for patients with type 2 diabetes associated with changes in HbA_1c and body weight. Research Design and Methods: The Cochrane Library, CINAHL, Embase, PubMed, PsycINFO, and Scopus databases were searched. Reports of randomized controlled trials published during 1975-2017 that focused on changing dietary behavior were selected, and methodological rigor, use of BCTs, and fidelity and intervention features were evaluated. Results: In total, 54 studies were included, with 42 different BCTs applied and an average of 7 BCTs used per study. Four BCTs-"problem solving," "feedback on behavior," "adding objects to the environment," and "social comparison" dand the intervention feature "use of theory" were associated with >0.3%(3.3mmol/mol) reduction in HbA_1c. Meta-analysis revealed that studies that aimed to control or change the environment showed a greater reduction in HbA_1c of 0.5% (5.5 mmol/mol) (95% CI 20.65, 20.34), compared with 0.32% (3.5 mmol/mol) (95% CI 20.40, 20.23) for studies that aimed to change behavior. Limitations of our study were the heterogeneity of dietary interventions and poor quality of reporting of BCTs. Conclusions: This study provides evidence that changing the dietary environment may have more of an effect on HbA_1c in adults with type 2 diabetes than changing dietary behavior. Diet interventions achieved clinically significant reductions in HbA_1c, although initial reductions in body weight diminished over time. If appropriate BCTs and theory are applied, dietary interventions may result in better glucose control.