Carol Ness of the SF Chronicle explains the Pennywise Eat Local Challenge:

It's a new wrinkle in the Eat Local Challenge, started two years ago by a small group of Bay Area women -- the Locavores. They issued an online call to people to spend one month trying to eat only foods from within 100 miles of where they live -- their foodshed.

That doesn't mean buying breads, say, from a nearby bakery -- it means trying to find breads made from flour ground from wheat grown within 100 miles (impossible in the Bay Area, by the way).

Ideally, every ingredient in every mouthful eaten for the month should come from the local foodshed -- down to the last grain of salt. Vegetables and meats are relatively easy. But bananas, coffee, tea and many spices are impossible. The point is to learn where your food comes from, save energy and keep farms from being paved over.

This is probably not that hard to do in the Bay Area, which is, after all, the demesne of Alice Waters, but trying to imagine doing this in New York—I think it would pretty much mean buying nearly exclusively from farmer's markets and Whole Foods, unless you have the time to visit a bunch of specialty shops. I'm sure the food would be delicious but wowza, the price tag!

Anyway, the Chronicle got three households to try the Challenge for a week: new parents and restauranteurs Nicholas Petti and Jaimi Parsons, who decided to include something they've foraged themselves in every meal; staff writer Jane Tunks, the car-less urbanite who buys everything in the city; and retirees Debbie and Rob Morse, who already follow a 75% local diet. Predictably, the Morses had the easiest time of it (they had a lot of free time to track food down) and Tunks the hardest (it killed her social life because she couldn't go to restaurants or bars), but all three households had different problems, as well as different ways of keeping within budget and finding ingredients.