An interesting and hopeful thing has happened in the past year without many people realizing it: "food miles" entered the public lexicon, and not as some hair-brained concept coming from hairy-headed hippies, but as a serious way of thinking about the social and environmental impacts of what we eat.

"Food-miles are a great metaphor for looking at the localness of food, the contrast between local and global food, a way people can get an idea of where their food is coming from," said Rich Pirog, associate director of the Leopold Center for Sustainable Agriculture at Iowa State University.

Pirog should know. He's Mr. Food Miles. Pirog carried out the research that found that foods travel on average "1500 miles from field to fork". In fact, it's even farther if you consider that his study was focussing on the average distance produce travels from the point of production to midwestern markets. For the East Coast, the distance is closer to 2500 miles.

Pirog is careful to point out that food miles are just one indicator of food's environmental impact and other things need to be plugged into the calculation, for example, how the food was produced before it hit the road. Still, food mileage is a concept that people can get their head around. With gas at $3/gallon, we know that getting good mileage is important and that some cars are better than others. Tuning into our food mileage is not just about ruling out the bad options - the infamous 3000 mile Caesar salad - but discovering the many good options out there, including some just down the street from us. Heck, we might even make a new neighbor.

If a metaphor can do that, it's a very powerful one indeed.