SAMPLE AND STUDY DESIGN. The sample will consist of children and adolescents (aged 8-16) referred to the Obesity Outpatient Clinic at Haukeland University Hospital. Criteria for admission to the clinic is an (IOTF) isoBMI of > 35, or a isoBMI > 30 with obesity related co-morbidity. Based on current clinic data, estimations suggest that about 60 families of children with severe obesity will be referred to the Obesity Outpatient Clinic every year and be offered treatment. Recruitment will start in February 2014 and will continue in 2015 and 2016. After consenting to participation and completion of the initial assessments the families will be randomized to either FBSFT or treatment as usual (TAU). After one year the families randomized to TAU will be offered the FBSFT treatment. Measurement points for the most important outcome measures will be pre-treatment, post-treatment (at approximately 6 months), at 12 months, 18 months and 24 months.