My thinking is this: by the time that organic carrot, lettuce, or apple comes from California -- and it seems all Whole Foods produce comes from California -- it had might as well be dipped in diesel fuel, and that's not even considering the water politics of our largest state. Local farmers markets are better, but unless you want to subsist on apples, leeks, and winter squash there needs to be another option.
A certain "gigantic" local grocery chain with the charms of a Turkish prison, on the other hand, takes the trouble to sell local produce, albeit grown by conventional agriculture. The counterintuitive choice is the environmental choice. So I hold my nose. Literally.
Haven't thought about the fuel you need for food? Read The SUV in the Pantry