I’ve long sung the praises of buying fruits and vegetables as close to home as possible. In my book, Perfect Weight America, I urged consumers to seek out local, sustainable alternatives to mainstream food. When you choose healthy, organic foods grown in your region, you not only improve your personal health, but you are also taking weight off the planet.

I asked Trent Hendricks, owner of Hendricks Farm and Dairy in Grantham, Pennsylvania, why is it important to consume local and sustainable meat and dairy products. He said this question can be answered on several levels.

“First, there is an argument that believes food produced in the same environment as the consumer lives in will lead to the greater health of that consumer, based on the foods’ ability to survive that environment,” Trent said. “Second, there is the aspect of community building, supporting businesses on a local level, and returning dollars to the region in order to build strength and longevity in our communities, maintaining open spaces, and environmental balance. Third, and perhaps most importantly, local agriculture has the potential to reduce our carbon footprints, thereby protecting and healing the environment. As greater demands are placed on our resources, it behooves us to consider the ramifications not only for ourselves but for future generations as well.”

Wal-Mart’s decision to purchase and sell more than $400 million of produce grown by local farmers should be terrific for the planet because of all the diesel fuel that will be saved from trucking fruits and vegetables halfway across the continent. Wal-Mart said it used to buy all its peaches from a few suppliers, but under this new direction to buy local, the huge retailer will be buying 12 million pounds of peaches from farms in 18 states.

What does Wal-Mart consider to be “locally grown”? That’s a great question. Their answer is that anything farmed within a state’s boundaries is considered locally grown. In the future, you can look for signs near produce to indicate that the fruit or vegetable was grown in that state. Wal-Mart shoppers in Arizona can look for more than falling prices—they should be able to grind Grand Canyon sweet melons in the produce section. New York residents can walk down aisles touting state-grown eggplant.

Of course, I have to mention the Law of Unintended Circumstances, meaning that we don’t know how Wal-Mart’s entrance into local foods affects farmers markets, which I have long supported. As any mom-and-pop outfit will tell you, it’s impossible to compete with Wal-Mart’s incredible purchasing power.