Background and Objective:
With the rise of type 2 diabetes (T2D) worldwide, dietary interventions are becoming increasingly important for disease control. However, despite the differing potential advantages of individual and group dietary interventions, there is limited evidence regarding the effectiveness and cost-effectiveness of individual compared to group dietary interventions. The objective of this review is to compare the effectiveness of individual versus group dietary intervention for T2D adults on metabolic parameters and dietary adherence.

Methods:
Cochrane CENTRAL, CINAHL, EMBASE, MEDLINE, and Psych INFO were searched for studies comparing the effects of individual versus group T2D dietary intervention. Our search focused on randomized controlled trials and controlled before-and-after studies of at least six months duration measuring glycemic control. Trials were included when diet modification was the main component, either through direct prescription of a diet or meal replacement or nutrition education of T2D adults. Intervention assessed was individual dietary education, while the comparator was group-based dietary intervention, including family, peers, or laypeople (neighbors, friends, or coworkers). Data generated from the search were managed using Endnote Version 7. Quantitative data synthesis were performed where studies were homogenous in characteristics and provided adequate outcome data for meta-analysis. Otherwise, data were synthesized using the narrative synthesis approach. Trials were assessed for risk of bias (Cochrane Risk-of-Bias, version 2.0) and overall certainty of evidence (GRADE).

Discussion:
Poor dietary adherence can severely affect a T2D patients health and well-being; therefore, the best method of delivering dietary education is a critical component of preventing and managing the disease. This review will provide a crucial summary of evidence regarding the effectiveness and/or cost-effectiveness of individual versus group delivery of patient dietary intervention. Implications for T2D prevention, policy, practice and future research will be discussed.