The purpose of this study was to investigate the response of participants in the first three Stages of Change (SOC) to a preparation stage-tailored intervention to increase fruit and vegetable (F&V) consumption. An on-line survey was delivered to 400 university employees, and included questionnaires about their demographic information, SOC, self efficacy (SE), and decisional balance (DB). One hundred fifty six (39%) responded to the survey. A total of 40 were selected from the first three stages, precontemplation (PC), contemplation (C), and preparation (P), and were assigned into two groups (PC/C and P) with consideration to the best possible matching in age, gender, income, education, and smoking status. Employees in both groups received the same intervention which was composed of four 1-hour sessions given over four consecutive weeks. Outcomes (F&V, SOC, SE, and DB) were measured at every session, and were also measured at weeks 5, 6, and 20 following the intervention.
At baseline (the response to the survey), the majority of the 400 employees were in the contemplation and the maintenance stages (34.9 and 34.3% respectively). Most of them reported positive perception and self confidence of consuming 5 servings of F&V everyday. Employees who were greater than 50 years old and held a PhD degree were more likely to consume five servings of F&V every day. During the intervention and until week 5, all employees increased their F&V, SE and DB and moved an advanced along SOC. However, employees in the PC/C group failed to maintain the change after week 5, and relapsed back to the baseline measures. The repeated measure MANOVA revealed a statistically significant interaction between the intervention and time which suggests that the intervention had a different effect on the employees in the two groups (i.e., relapse for the PC/C group and maintenance of the P group). These results suggest that individuals who receive intervention not matching their SOC are at higher risk to relapse. Stage-tailored interventions may be more cost-effective when delivered to the appropriate individuals.