The book, Just Food: Where Locavores Get It Wrong and How We Can Truly Eat Responsibly, by James E. McWilliams, gives a very interesting take on the concept of 'eating locally'. He gives a unique argument that globally produced food is more efficient from a fuel standpoint than locally produced food.
He includes very extensive research to prove his case, which he describes in thorough but easy-to-understand detail. Take a look at what he says about organic farming and genetically-modified crops! If you were uncertain about whether local food production and consumption is beneficial from a green standpoint and an economic standpoint, you should check out Just Food: Where Locavores Get It Wrong and How We Can Truly Eat Responsibly