In a change setting (employees having a regular medical appointment), two interventions (one for nutrition change and one for activity change) will follow and assessments over a time period of 12 to 20 weeks will be conducted afterwards. Study participants in the intervention groups receive an interactive, computerized expert system (Intervention Group, IG). Individuals in the waiting control group (WCG) get nothing. Employees (N = 1000) will be recruited at their regular medical appointment. Study participants will be followed up over three measurement points: One to nine weeks after T1, T2 will take place. Five to 13 weeks after T1 the T3 measurement will be conducted.