Intrepid eaters Jane and Michael Stern chew across U.S., gathering list of 'must eat' spots ahead of 'nutrition police,' whom they fear will make whoopee pies, fried chicken illegal. Along the way, they chronicle and sustain regional food traditions. And: Anthology of essays, notes from unfinished 1930s Federal Writers' Project shows that many regional classics were disregarded (click 'See also').