It takes about a tablespoon of diesel fuel to move one pound of freight 3,000 miles by rail; that works out to about 100 calories of energy. If it goes by truck, it’s about 300 calories, still a negligible amount in the overall picture. (For those checking the calculations at home, these are “large calories,” or kilocalories, the units used for food value.) Overall, transportation accounts for about 14 percent of the total energy consumed by the American food system.
A single 10-mile round trip by car to the grocery store or the farmers’ market will easily eat up about 14,000 calories of fossil fuel energy. Just running your refrigerator for a week consumes 9,000 calories of energy. That assumes it’s one of the latest high-efficiency models; otherwise, you can double that figure. Cooking and running dishwashers, freezers and second or third refrigerators (more than 25 percent of American households have more than one) all add major hits. Indeed, households make up for 22 percent of all the energy expenditures in the United States.
There are many good reasons to eat locally but reducing transportation emissions isn't one of the major ones.