Like many great adventures, the 100-mile diet began with a memorable feast. Stranded in their off-the-grid summer cottage in the Canadian wilderness with unexpected guests, Alisa Smith and J.B. MacKinnon turned to the land around them. They caught a trout, picked mushrooms, and mulled apples from an abandoned orchard with rose hips in wine. The meal was truly satisfying; every ingredient had a story, a direct line they could trace from the soil to their forks. The experience raised a question: Was it possible to eat this way in their everyday lives? Back in the city, they began to research the origins of the items that stocked the shelves of their local supermarket. They were shocked to discover that a typical ingredient in a North American meal travels roughly the distance between Boulder, Colorado, and New York City before it reaches the plate. Like so many people, Smith and MacKinnon were trying to live more lightly on the planet; meanwhile, their "SUV diet" was producing...