For the first time in human history, more than half of the global population live in urban environments. To sustain urban habitats and their inhabitants, we must plan, design and think of cities as ecological systems, create healthy urban metabolisms and reconsider the relationship between cities and their hinterland. Climate change, peaking oil supplies, increasing levels of pollution, scarcity of fresh water, biodiversity loss, toxic food scares, and escalating violence are just some of the reasons why new patterns of urban living need to be developed. There is a great potential in urban areas to produce more, waste less and contribute to the ecological balance (restoration of the urban metabolism). Cities can become cyclers instead of sinks. The settlements we live in affect the choices we make and the way we live, as well as the level of impact we have on the planet's finite resources. A radical shift is required in the current approach to the design of human settlements and the food systems that feed the populations.