In France, the midafternoon snack is a frequent habit among children usually characterized by the consumption of fatty, sweet and high-energy-dense foods. If eating behaviours remain flexible and can evolve throughout the life, they are already strongly established during childhood. In this context, improve food habits in terms of midafternoon snack seem important. The thesis aim was therefore to assess the effectiveness of levers aimed at promoting healthy snack choices within mother-child dyads. A first experiment was conducted in order to assess the impact of a nutritional labelling system, the Nutri-Score, on the nutritional quality and on the liking of the snacks chosen within mother-child dyads. The results showed an improvement in th...