In Mediterranean countries, short food supply chains, limiting the number of intermediaries between producers and consumers, are not new, but have been renewed in the last twenty years. In France, especially, the new requirements of consumers regarding food quality pushed the Ministry of Agriculture, in a context of agricultural economie crisis, to establish an official definition of short food supply chains in 2009, as well as a national programme to favour their development. However, while the State little invested in this programme, a large diversity of actors (citizens, associations, farmers' groups, agricultural extension organisms, entrepreneurs, local authorities...) has been engaged to renew these chains, through promotion, creation of innovative forms, structuration of networks ... This movement has been deeply reconfiguring food environments, not only by making more visible and accessible the supply of 'local' and 'quality' food, but also by catalysing new social interactions and relations around these chains. Based on the contribution of economic and network sociology, this communication will point out and discuss how these interactions and relations can favour the evolution of food practices towards more sustainable diets, from a longitudinal analysis of different chains, including short food chains in food aid. Our analysis thus highlights new levers to favour sustainable diets as well as contributes to open a new research agenda about the 'determinants' of food practices, and of food practices' transition.