In cooperative food activities, the pervasive term ‘community’ plays a performative role in stimulating congenial activities which build enthusiasms and expand alternative food-supply chains. As exemplified by London’s food initiatives, community-building entails several forms of social innovation, e.g. enhancing socio-political capabilities, fulfilling unsatisfied needs and redefining societal problems. In particular, these initiatives recast ‘food poverty’ as a socio-cultural poverty which warrants a system change. They reframe ‘assets’ as people’s capacities, e.g. by defending amenities for lower-income people, re-commoning urban spaces, and resisting land-assetisation. Social innovation depends on novel forms of agency in two main processes: capabilities development for a food culture, and multi-actor territorial outscaling. Together these build solidaristic interdependencies around a vision of food sovereignty for social justice. To gain more resources, they accommodate or stretch the criteria of funding bodies; they strategically engage with local authorities as partners and/or critics. London’s food initiatives face challenges in combining these diverse aims and activities.