Small islands are vulnerable to climate change, and at the same time contribute to local and global environmental problems with the intensification of tourist activities. Whereas there are many studies on the resource requirements or environmental impacts of small islands, there are few efforts to integrate information that is often analysed separately. Metabolic analysis, beyond quantifying biophysical flows, studies how society transforms these flows to reproduce the identity of the whole. This study applies the Multi-Scale Integrated Analysis of Societal and Ecosystem Metabolism (MuSIASEM) approach, to analyse the environmental and economic performance of different economic activities in the Mediterranean island of Menorca (Spain). The openness of the metabolic system (observed in the dependence on imports) and externalization of environmental impact are illustrated using the examples of the cheese and tourist industry. The results show that a higher economic performance in terms of value added is associated with activities in industry and services with a larger dependence on imports of “external resources” – fuel for transportation, milk for cheese, seasonal workers and “paying capacity” of tourists. This dependence reduces local environmental pressures and also adaptation capacity, since decisions made in Menorca may have limited impact elsewhere. Local agriculture depends less on external resources but it is limited by the low economic productivity of land and labour. An integrated analysis of the relations between metabolic rates and densities of flows in the different compartments of the society provides a holistic picture of sustainability issues and can contribute to decision-making by avoiding partial information.