NEW YORK - McDonald's has so far prevailed in the lawsuits that have asserted it is partly to blame for its customers' bulging waistlines. But a new lawsuit filed in federal court in San Francisco insists the burger giant has failed in its promise to move to a healthier cooking oil, and it is being brought not by fry-eaters but by Kathy Fettke, a "personal coach" and infomercial pitchwoman who "is living her dream by helping others live their dreams." Fettke, who has also worked as a television host and actor--she played a bridesmaid in Flubber--is married to the similarly...