Food and agriculture are by far the largest employers of people on the planet. In an international programme, sponsored by the International Association of Research Universities (IARU), three universities (Australian National University, Copenhagen University, Denmark and Todai (Tokyo) University, Japan) have been collaborating to study the food systems of the capital regions of Canberra, Copenhagen and Tokyo. The reasons for choosing these capital regions is that they scale in terms of population density from 0.1 persons per ha (Canberra) to 4 persons per ha (Copenhagen) to 40 persons per ha (Tokyo). Our interest has been to distinguish the notion of food security from that of food sovereignty for the three capital regions. Data will be presented on changes in crude food consumption of the capital regions from 1965 to 2005 and show how changes in food consumption have stemmed from imports, indigenous production and export. We also ask the questions as to what changes in crude consumption mean for the trading of food and land services as between the capital regions and globally. The policy issues raised by this and similar studies are the links between carbon trading and food trading, the question of what it means to eat locally and who should pay for emissions in relation to food trade.