In the four-year research program HealthPro, Centre of Expertise Healthwise examines the extent to which health programs (such as Menzis SamenGezond) are effective in achieving a healthy lifestyle. Can an online program contribute to sustainable behavioral changes? And does this contribute to a reduction in healthcare costs? Does it primarily attract people who already have a healthy lifestyle, or does the program also stimulate people with a less healthy lifestyle? And how can people be encouraged to actively participate in the program? These are unanswered questions that are not only academically relevant, but can also lead to new insights for managers and policy makers who want to contribute to a healthy lifestyle.