By Dave Sherwood AUGUSTA, Maine (Reuters) – Maine’s top health official on Monday proposed banning the purchase of soda and candy under the federal aid program known as food stamps, describing the move as needed to counter an “alarming epidemic of obesity” among the state’s poor. In their formal request to the U.S. Department of Agriculture, which must approve any change in rules related to the federal Supplemental Nutrition Assistance Program, state officials said the shift would help control the rising costs of healthcare for overweight, low-income patients. A 2012 study by a University of Maine researcher put the annual medical costs of obesity in Maine at $452.7 million.