Physical activity prevents several health-related diseases for children and adolescents, and risk factors are significantly increased for physical inactive children and adolescents. In Denmark every fifth child is overweight, which typically is related to unhealthy eating habits and poor exercise habits. Studies have shown, that parent-involvement is important for child weight loss, and a way to include the parents is through family-based health interventions. This type of intervention can help the families change their eating- and exercise habits and hereby prevent child obesity. Purpose: The purpose of this study is to investigate whether changing of eating- and exercise habits occur, after participation in a family-based health intervention. Method: The data was collected through three semi-structured family-based interviews, lasting 90-120 minutes. The interviews occurred 9-24 months after the families had completed the intervention SÅ LETTER VI in Mariagerfjord municipality. The findings from the interviews have been analyzed according to Interpretative Phenomenological Analysis, and divided into three thematic categories, which are discussed in relation to relevant research and theories. Results and conclusion: The findings show that all families have changed their eating- and exercise behavior as result of participating in SÅ LETTER VI. However, the findings indicate that the changed behavior is not established as habits.