The decision that Medicare will pay for screening and counseling services to help obese patients lose weight has opened an old debate about who can best help people slim down. Top national weight-loss experts salute the ruling as good news, but they are concerned that many doctors and their staffs are ill prepared and haven't the time to help obese patients. "This is an incredibly positive move by the government in recognizing obesity as a contributor to many of our health problems," said Donna Ryan, an obesity researcher at the Pennington Biomedical Research Center in Baton Rouge, LA. "But the devil is in the details, and many physicians have no training in weight-loss counseling — zero."