Given our struggling economy as well as the national struggle to maintain our waistlines, cycling is enjoying a renaissance as more than 57 million people in the United States use bicycles regularly. Now "Bicycling"'s Fit Chick presents a brand-new, 12-week weight-loss and exercise plan for beginner and experienced cyclists alike.Whether readers have just a little bit of weight to lose or a lot, "Bike Your Butt Off "will help them meet their weight-loss goals in no time, thanks to its expert-tested food an