The Effect of Workplace Interventions With a Dietary Component on Organisational‐Related Outcomes: A Systematic Review of the Evidence

BACKGROUND: For employers, investing in workplace wellbeing programmes is considered in the context of potential cost-savings related to employee absenteeism, productivity, recruitment, retention, and company reputation. This review evaluated the effectiveness of workplace interventions with a dietary component on organisational outcomes. METHODS: This systematic review was registered in the International Prospective Register of Systematic Reviews (CRD42023454673). Six databases (Medline, Embase, Cochrane Library, Web of Science, APA PsycINFO, Business Source Complete) were searched for studies from 1990 to September 2023. Studies were screened in duplicate and included if they were a randomised controlled trial (RCT) or quasi-experimental (QE) design, conducted in a workplace setting in a high-income country, the intervention included a dietary component, and they reported organisational-related outcomes. A synthesis without meta-analysis was conducted and risk of bias was determined using study design specific Joanna Briggs Institute critical appraisal tools. RESULTS: From 29,418 articles retrieved, 168 met the inclusion criteria. Most studies (68.4%) used a QE design and 76% were conducted in North America. Provision of educational materials (62.5%) and group nutritional education (56.0%) were the most frequently reported nutritional intervention components. Most studies (91.7%) combined nutrition with another lifestyle component, mainly physical activity (82.0%). From the studies 407 measurements were evaluated across 50 organisational outcomes. The most frequently reported outcome was absenteeism (87 studies) with most (75.9%) showing no significant intervention effect. Healthcare costs were evaluated in 65 (38.6%) studies with 41.5% indicating positive effects. Return on Investment (ROI) was evaluated in 28 (16.6%) studies and had the largest proportion, 89.3% reporting a positive effect (range of ROI negative 3.9 to positive 15.6). Overall non-RCTs were classified having 'moderate' risk of bias and most RCTs being at 'high' risk of bias mainly due to lack of blinding, cluster design and incomplete follow up. CONCLUSION: Workplace health and wellbeing programmes with a nutritional component may have a beneficial impact on healthcare costs; however, the evidence is heterogenous and largely based on interventions in the USA. This review identifies the need for improved reporting of interventions and outcomes in evaluations to assess organisational benefits.