Marleen A. van Baak

Summary Background Family‐based approaches have been reported to be effective in improving overweight or obesity in children. Objectives To investigate the relationship of changes in body mass index and metabolic parameters between adults with overweight or obesity and their children during a weight‐maintenance family‐based dietary intervention. Methods In a multicentre randomized controlled trial, families with at least one parent with overweight or obesity and one healthy child aged between 5 and 18 years, of which the parents completed an 8‐week weight‐loss phase successfully, were randomized into five different dietary intervention groups to achieve weight maintenance for 6 months. Anthropometric parameters and body composition were measured and blood samples were collected before and after the dietary intervention. Data were analysed using Pearson correlation coefficient analyses and multiple linear regression analysis adjusted for diet group, centre, child's sex and age. Results A positive association was found between the change in body mass index (BMI) of the mother and change in BMI‐for‐age Z‐score of first and second child (std = 0.248, p = 0.000; std = 0.326, p = 0.000, respectively). The change in BMI of the father was only significantly associated with the change in BMI‐for‐age Z‐score of first child (std = 0.186, p = 0.031). No consistent pattern of associations between parents and children was found for homeostatic model assessment for insulin resistance, fasting glucose and fasting insulin. Conclusion This study supports the inclusion of parents into family‐based dietary approaches for weight management of their children regardless of the child's weight status in eight different countries throughout Europe.