So what are we to make of the fact that Lay's potato chips now promote themselves as a locally-grown food? Do we thank Michael Pollan for this?

In case you missed the news, Frito-Lay, the world's biggest snack food maker and a unit of PepsiCo., this week said it will market Lay's potato chips ("America's favorite potato chip") by putting the spotlight on the 80 farmers in 27 states who grow  potatoes for Lays. By typing product codes from a bag of chips into a website using what the company calls a Chip Tracker – you can check it out here – consumers can learn where their chips were grown and made. Just the other day, I wrote that traceability is a big deal, but I never expected to be able to track the supply chain of a potato chip.

USA Today quotes a Frito-Lay exec:

"Knowing where food is made and grown is important to consumers," says Dave Skena, vice president of potato chip marketing at Frito-Lay. "Sharing with consumers how regional we are is relevant and compelling."

TV ads will feature the local farmers, the New York Times reports:

One is Steve Singleton, who tends 800 acres in Hastings, Fla.

"We grow potatoes in Florida, and Lays makes potato chips in Florida," he says in the ad. "It's a pretty good fit."

And you thought eating local was about shopping at your neighborhood farmer's market. How naïve.

It's no surprise, really, to see Big Ag is jumping aboard the "local" movement. My Giant supermarket touts "Delmarva" chickens, meaning they come from the vast chicken farms on the eastern shores of Delaware, Maryland and Virginia. They may be local, but, alas, their chicken poop is also responsible for much of the pollution in the Chesapeake Bay.

Wal-Mart, too, says it is buy more local food, for practical as well as environmental reasons. It's fresher, cheaper to ship and helps counter the notion that Wal-Mart is a giant chain store that doesn't care about local communities.

As Frito-Lay's Skena put it: "This is celebrating the notion of community."

Oh, please.

Of course, American growers have a compelling reasons to argue that local is superior to long distance food. Again, from The Times:

For some big agricultural interests, promoting local food has a protectionist bent. Sales of Virginia apples were hurt a few years ago when Chinese apples flooded the market, said Martha Moore, director of governmental relations for the 38,000-member Virginia Farm Bureau.

Those kinds of threats from imported food is one reason her agency started a local food marketing program last year.

"If promoting local agriculture will help America to become food independent, that's what we want," she said.

Well, sure. But if we close our doors to Chinese apples, Chilean grapes or Brazilian sugar (which we do, at least in the case of sugar), what, then, are we going to say with other countries decide to shut out American wheat—or movies or software.

And as long as we're on the subject of grapes, next time you pack a lunchbox for little Joey or Judy, ask yourself what you've accomplished by throwing in a "local" bag of chips instead of a "foreign" bunch of grapes. Junk food is junk food, even if it's made right around the corner.

Now I've got no beef with Frito-Lay. The company takes environmental issues seriously. A Frito-Lay plant in Casa Grande, Arizona, aims to cut its electricity and water usage by 90%, and within a couple of years, the plan will "run almost entirely on renewable energy and recycled water while reducing waste going to the landfill to less than 1%," the company says. Frito-Lay has set big audacious goals to reduce its environmental footprint. I interviewed a Frito-Lay sustainability exec named Dave Haft at the Milken conference a year ago, and he was a really impressive guy. If I were a fan of potato chips instead of a pretzels guy, I'd buy Lay's.

The trouble is, local is a slippery idea. Indeed, there's no one quality or attribute when it comes to food (or anything else) that equals "good." Not organic, or Fair Trade, or local or, for that matter, low-fat. We need to find ways to think more holistically about the impact of the things we buy or consume. Over time, I suspect, companies will move to create broader eco-labels that take into account the entire life cycle impacts of the things they sell.

Are "local "Lay's a step in that direction? Not really. But if all they do is get people thinking about the environmental impact of the food choices, that can't be a bad thing.