For most of human history, if you expended more energy in acquiring food than you derived from it, you would eventually starve. But in the fossil fuel era, the amount of energy we use in the production of food exceeds the energy we derive from food by a factor of 10 (Heinberg, 2011, p 130). By accessing hundreds of millions of years of stored sunlight we have evaded the old expenditure versus consumption equation, while swelling the population from 1 billion to 7 billion in less than two centuries.

Famines and starvation have not disappeared, obviously, because such profligacy has been bestowed by the affluent largely on themselves (Patel, 2007). Developed nations have devoured the earth's inheritance, leaving countless millions, both now and in the future, to rely on the scraps. But regardless of when oil, gas and coal peak, or whether new miracle technologies emerge, there must come a time when either it is no longer practicable to access those fuels, or we decide to limit the emissions they create, or both. In other words, the energy equation is on its way back.

None of this should be surprising since food has long occupied a central place in political and social policy conflicts (Vernon, 2007, Chapter 8). In the late 1970s the then Leader of the Opposition, Margaret Thatcher, pointed to shopping baskets that seemed to shrink year after year. ‘Unlike inflation-happy socialists,’ went the message, ‘wives and mums know the real cost of living.’

Yet as is now clear, it is difficult for wives, mums or any of us to know what powerful market actors do not want us to know. Companies (and governments) depend on consumer passivity, complicity and ignorance about what goes into food and what consequences it has (Singer and Mason, 2006, pp 8-12). The industrialisation of farming alienates consumers everywhere from the food production process, but this blindness is especially virulent where corporations control the food chain. The consumer revolution took social contexts out of shopping, constructing food as nothing more than an economistic series of cost-benefit decisions made by ‘active’ customers in supermarkets humbly grateful for their business.