Systematic review and meta-analysis of remotely delivered interventions using self-monitoring or tailored feedback to change dietary behavior

Background: Self-monitoring (SM) of diet and tailored feedback (TF) have been suggested as tools for changing dietary behavior. New technologies allow users to monitor behavior remotely, potentially improving reach, adherence and outcomes. Objectives: We conducted a systematic literature review and meta-analysis to address the following question: Are remotely delivered standalone (i.e. no human contact) interventions that use SM or TF effective in changing eating behaviors? Design: Five databases were searched in October 2016 (updated in September 2017). Only randomized controlled trials published after 1990 were included. Trials could include any adult population with no history of disordered eating which delivered a SM or TF intervention without direct contact and record actual dietary consumption as an outcome. Three assessors independently screened the search results. Two reviewers extracted the study characteristics, intervention details, outcomes and assessed risk of bias using the Cochrane tool. Results were converted to standardized mean differences and incorporated in a three-level (individuals and outcomes nested in studies) random effects meta-analysis. Results: Twenty six studies containing 21,262 participants were identified. The majority of studies were judged to be unclear or at high risk of bias. The meta- analysis showed dietary improvement in the intervention group compared to control with a standardized mean difference of 0.17 (0.10, 0.24; p<0.0001). The I2 statistic for the meta-analysis was 0.77, indicating substantial heterogeneity in results. The one-study removed sensitivity analysis showed that no single study excessively influenced the results. Conclusions: Standalone interventions containing self-regulatory methods have a small but significant effect on dietary behavior and integrating these elements could be important in future interventions. However, there was substantial variation in study results which could not be explained by the characteristics we explored, and there were risk of bias concerns with the majority of studies