"Les Bons Comportements Alimentaires" campaign, meaning Right Food Behaviours addresses children eating patterns as a whole and is part of the program « Vivons en forme » (meaning: "lets be fit and healthy!") or VIF® . VIF®. is a program driven by FLVS, a non-profit organization which for more than 10 years has proposed preventive health programs targeting French children, following the former EPODE program. Its main objective is to promote health and well-being by focusing on the prevention of childhood obesity and overweight and on the social inequalities regarding food intake and physical activities. VIF is currently acting in 252 French towns, most of which are in poor environments. It has already touched 4 million people, families and children. It is aiming to help families to modify their health behaviours deeply and lastingly thanks to the commitment of local actors. “Les Bons Comportements Alimentaires” campaign has a specific focus on the portion sizes theme: which portion for which child, regarding his/her age? And which portions of the different ingredients of a diet? Its main behavioural objectives are: For the school-meals staff: to help them give the right portion in accordance with nutritional recommendation linked to the child’s age. For the children of elementary school: to raise their good practices regarding treats such as candies, sugary drinks, chips, etc., however adding also emotional and sensory enjoyment experiences, and offering mindful eating apprenticeship. For children and their families: to adapt servings to the child’s needs - especially on meat, fries, - and including all kinds of treats. Focus groups and interviews were conducted with the target audience to ensure understanding and with secondary audience to ensure there are no unintended negative effects. Both targets and local actors were included in a participative process aiming to identify barriers and motivations for change and to co-create the coming campaign in order to lesson to and involve everyone in achieving the campaign objectives. Starting from audience and local actors’ insights and proposals, the objectives were then to define a tangible and emotional design for innovative good practices appealing for children and their families. A Living Lab phase permitted to collect feed back, returns on experiences actors, thus becoming the “ambassadors” of the campaign and to reach out to the final target. The final campaign consists in forming professional actors (canteen staff and extracurricular staff) at a local level to support change behaviours of canteens staff, children and families regarding food portions sizes and treats. The campaign is still on-going but some partial results are provided: professionals’ satisfaction about the 145 training sessions; the food waste in school canteens in Saint André-Lez-Lille, one of the first towns to adopt the campaign, which has halved, suggesting that children are receiving servings that are more adapted to their needs. At a general level, VIF program encounters remarkable results on children weights in the involved towns.