Alice Waters, of Berkeley’s Chez Panisse, made sourcing regional ingredients de rigueur in the seventies, but her efforts were eclipsed in the eighties by stagy chefs who outdid one another with exotic fare supplied by far-flung purveyors. (Who knew an entrée could rack up more mileage than Air Force One?) Today, a renewed interest in eating close-to-homegrown has started a trend—the rise of the locavore. Pioneering restaurants are leading the way with menus based entirely on cutting food miles (the distance ingredients travel to reach the plate), which minimizes greenhouse-gas emissions from fuel-hungry trucks and trains—and helps microeconomies, to boot. Oliver Rowe, of Konstam (2 Acton St., Prince Albert; 44-207/833-5040; dinner for two $122), has set himself the task of cooking whenever possible with products grown in Greater London. His dishes use honey from Barnes, button mushrooms from a farm under the A406 (North Ring Road), and carrots from a garden in Brick Lane, in the East End. Most of his meals clock in at under 100 food miles—2 percent of the distance that the average piece of produce travels in Britain. Now that’s a guilt-free dinner.