Impact of Work Site Health Promotion on Stages of Dietary Change: the Working Well Trial

The stages of change construct has been applied to healthful dietary behavior in cross-sectional studies. This report examines associations of stages of change with diet prospectively and addresses whether (1) baseline stage of change predicts participation, (2) forward changes in stage movement were greater in treatment work sites, and (3) change in stage was associated with adoption of healthful diets, using data from a cohort of 11,237 employees. Findings indicate that persons in later stages of change reported higher participation levels. Employees from intervention work sites who were in preaction stages at baseline were much more likely to shift into action and maintenance stages than controls. Changes in dietary stage of change were associated with decreases in fat intake and increases in fiber, fruit and vegetable intake. Net change in diet due to the intervention was modest. Stage of change appears to be useful for understanding mediators of health promotion intervention effectiveness.