But do food miles, the distance edibles travel from farm to plate, give an accurate measurement of the environmental impact, especially where greenhouse gas emissions are concerned?
“Food-miles are a great metaphor for looking at the localness of food, the contrast between local and global food, and a way people can get an idea of where their food is coming from,” said Rich Pirog, associate director of the Leopold Centre for Sustainable Agriculture at Iowa State University.
The problem with food-miles is that they don’t take into account the mode of transport, methods of production or the way things are packaged, and all of these have their own distinct impact on emissions of carbon dioxide, a climate-warming gas.
Take the case of the well-travelled Idaho potato and its closer-to-home cousin from Maine. For a consumer on the US East Coast, the Maine potato seems the winner in the local food derby.
But Maine potatoes get to market by long-haul truck while Idahos go by train, a more energy-efficient mode of transportation, so they have a smaller carbon footprint even with a larger number of food-miles.
Food, fuel and freeways
The idea of food-miles, or more properly food-kilometres, began in Sweden and Britain, but Pirog and others started looking into the matter in the United States in 2001 in a paper called “Food, Fuel and Freeways,” available online.
The United States came late to the local food movement, except for high-end eateries that featured their offerings’ provenance as a selling point in the 1970s. Until then, imported food was considered a status symbol, no matter what condition it was in when it finally arrived at the table.
Another difficulty with the food-miles measurement is that the most accurate versions of this calculation deal only with produce, not with prepared foods that contain many ingredients from many sources.