This meta-analytic review critically examines the effectiveness of workplace interventions targeting physical activity, dietary behaviour or both on weight outcomes. Data could be extracted from 22 studies published between 1980 and November 2009 for meta-analyses. The GRADE approach was used to determine the level of evidence for each pooled outcome measure. Results show moderate quality of evidence that workplace physical activity and dietary behaviour interventions significantly reduce body weight (nine studies; mean difference [MD]-1.19 kg [95% CI -1.64 to -0.74]), body mass index (BMI) (11 studies; MD -0.34 kg m⁻² [95% CI -0.46 to -0.22]) and body fat percentage calculated from sum of skin-folds (three studies; MD -1.12% [95% CI -1.86 to -0.38]). There is low quality of evidence that workplace physical activity interventions significantly reduce body weight and BMI. Effects on percentage body fat calculated from bioelectrical impedance or hydrostatic weighing, waist circumference, sum of skin-folds and waist-hip ratio could not be investigated properly because of a lack of studies. Subgroup analyses showed a greater reduction in body weight of physical activity and diet interventions containing an environmental component. As the clinical relevance of the pooled effects may be substantial on a population level, we recommend workplace physical activity and dietary behaviour interventions, including an environment component, in order to prevent weight gain.

ObjectiveTo investigate the effectiveness of a worksite social and physical environment intervention on need for recovery (i.e., early symptoms of work-related mental and physical fatigue), physical activity and relaxation. Also, the effectiveness of the separate interventions was investigated.MethodsIn this 2×2 factorial design study, 412 office employees from a financial service provider participated. Participants were allocated to the combined social and physical intervention, to the social intervention only, to the physical intervention only or to the control group. The primary outcome measure was need for recovery. Secondary outcomes were work-related stress (i.e., exhaustion, detachment and relaxation), small breaks, physical activity (i.e., stair climbing, active commuting, sport activities, light/moderate/vigorous physical activity) and sedentary behavior. Outcomes were measured by questionnaires at baseline, 6 and 12 months follow-up. Multilevel analyses were performed to investigate the effects of the three interventions.ResultsIn all intervention groups, a non-significant reduction was found in need for recovery. In the combined intervention (n = 92), exhaustion and vigorous physical activities decreased significantly, and small breaks at work and active commuting increased significantly compared to the control group. The social intervention (n = 118) showed a significant reduction in exhaustion, sedentary behavior at work and a significant increase in small breaks at work and leisure activities. In the physical intervention (n = 96), stair climbing at work and active commuting significantly increased, and sedentary behavior at work decreased significantly compared to the control group.ConclusionNone of the interventions was effective in improving the need for recovery. It is recommended to implement the social and physical intervention among a population with higher baseline values of need for recovery. Furthermore, the intervention itself could be improved by increasing the intensity of the intervention (for example weekly GMI-sessions), providing physical activity opportunities and exercise schemes, and by more drastic environment interventions (restructuring entire department floor).Trial RegistrationNederlands Trial Register NTR2553