The overall aim is to evaluate if a familybased intervention, targeting overweight and obese children and their parents, has a long-term positive effect on weight development and health of the children. The alternative hypothesis to the zero hypothesis is that the children with overweight and obesity who participate in a one-year intervention together with their parents, both at completion of the six months intervention and at long term follow up will have reduced their BMI-for-age z-score (Iso-BMI) and have adopted healthy habits. The behavioral models and educational strategies will be tailored (by age, gender etc.) and include both general information and practical learning sessions.

The investigators intend to perform a controlled clinical trial on interventions on a systemic level.

The target group is overweight and obese children between 6 and 10 years old, their parents, community administrators and public health nurses. The overall aim is to evaluate if a familybased intervention, targeting overweight and obese children and their parents, has a long-term positive effect on weight development of the children. The alternative hypothesis to the zero hypothesis is that the children with overweight and obesity who participate with their parents, both at completion of the six months intervention and at long term follow up (2 years) will have reduced their BMI-for-age z-score (Iso-BMI). The behavioral models and educational strategies will be tailored (by age, gender etc.) and include both general information and practical learning sessions. The program will offer guided active play, defined as spontaneous gross locomotor movement in which children engage to amuse and to occupy themselves.

Parents will attend to workshops intending to increase knowledge and awareness of family structure, healthy eating habits and practical suggestions for implementing healthy behaviors into everyday life. Parents will be educated on how to use these strategies at home, to further support their children in improving their behaviors. This community based study is the support by the local leadership and collaboration with locally based sports clubs. The primary outcome variable, child BMI-for-age z-score will be measured at referral, inclusion, after 6 months, and at 1 and 2 years post intervention. Secondary outcome variables, measured at inclusion and at the end of intervention, are child activity pattern, screen viewing time, eating habits, sleeping patterns and body composition as well as parent BMI, body composition, exercise habits, perception of health, experience of parenthood and level of parental stress.

Physical activity level as well as sleep duration and -quality will be recorded using biaxial accellerometers. A validated food diary will be used. The participants will also be asked to complete a questionnaire including questions about screen viewing time, self-perceived healt, sleeping patterns (children) and perceived autonomy support and autonomous regulations (parents).

Inclusion Criteria:

• Iso-BMI>25,
• able to participate in activity groups

Exclusion Criteria:

• Children being unable to participate in activity groups,
• parents not able to participate in group based and individual counseling