Abstract Several projects across Europe are focused on improving sustainability of public procurements; however, few of them are measuring the environmental savings achieved by specific policies through the application of environmental impact assessment indicators. In this paper, we calculate environmental savings by applying a carbon footprint analysis to three food policies implemented by the City of Turin (Italy) in the school catering service (school years 2012/13 and 2013/14). The policies are focused on (I) the production of food (with the requirement of integrated or organic products), (II) the geographical origin of the food (with the requirement of regional food provisioning) and (III) the improvement of urban distribution (with the requirement of shifting to natural gas vehicles). The climate change potential of five of the most consumed foods were studied according to three main phases of the supply chain: production (including all processes in a cradle-to-gate perspective), provisioning (focusing on the transportation from production sites to the peripheral food hubs of the city), and distribution (focusing on the transportation from the city hubs to schools). The results of this study highlight the different climate impacts of the three phases of the supply chain, in particular 61–70% of the greenhouse gases are emitted in the production phase, 6–11% in the provisioning phase and 24–28% in urban distribution. As a consequence, policies that affect production practices have the greatest potential for reducing the carbon footprint of the catering service. Other policies (such as those on transportation) can have controversial effects. Therefore, to improve planning of sustainability policies, the greenhouse gas emission savings achieved by each policy must be analysed in-depth.