The effectiveness of workplace dietary interventions: Protocol for a systematic review and meta-analysis

Background: The lack of evidence of the role of workplaces as settings for behaviour change delivery and the failure to recognise and address the complexity of the work environment has been acknowledged. This systematic review and meta-analysis will identify the effectiveness of dietary interventions in the workplace facilitating an understanding of what works, why and how by identifying key components of and examining the theoretical models of behaviour change underpinning successful dietary interventions in the workplace. Methods/design: We will conduct searches in MEDLINE, EMBASE, CINAHL, PsycINFO, CENTRAL and PubMed for studies that assess dietary interventions based within workplace settings in any country, of any length of time or duration of follow-up. We will include all randomised controlled trials (RCTs), non-randomised controlled trials (NRCTs), controlled before-after studies (CBAs) and interrupted time series (ITS) studies with a control group. Risk of bias of included studies will be assessed using a tool adapted from the Cochrane Public Health Review Group's recommended Effective Public Health Practice Project Quality Assessment Tool for Quantitative Studies. Meta-analysis will be conducted if appropriate, or a narrative synthesis will be conducted following the ESRC Narrative Synthesis Guidance. Discussion: This paper outlines the study protocol for a systematic review and meta-analysis that will identify, critically appraise, and summarise the relevant evidence on the effectiveness and implications of interventions to promote healthier dietary behaviours in the workplace. This review will give an overview of the evidence and provide a guide for development of interventions promoting dietary behaviour change in workplaces. Systematic review registration: PROSPERO CRD42015015175