Our contribution aims at pointing out how the food issue challenges metropolitan areas while at the same time identifying potential for sustainable urban planning. To that end, we investigate to what extent taking into account agricultural and food-related issues enables to rethink urban planning which is usually qualified as sustainable. Our analysis will be based upon the two French urban regions of Grenoble and Caen where participatory research was conducted through collective and prospective walks. These urban explorations, which provide insights on metropolitan spaces and the interrelations that underlie them, underly the disconnections of contemporary urban planning with the inhabitants, their vital needs and, more generally, the soil, while highlight working paths for a more nourishing, meaningful and rooted urban planning. By considering urban planning through the scope of agri-food stakes, we contribute then to the renewal of urban concepts and thus highlight three workshops aiming at further developing sustainable urban planning issues and tools.