Experts say Mississippians need to skip the gravy, say no to the fried pickles and start taking brisk walks to fight an epidemic of obesity. According to a new study, this Deep South state is the fattest in the United States. The Trust for America's Health, a research group that focuses on disease prevention, says Mississippi is the first state where more than 30 percent of adults are considered obese. Aside from making Mississippi the butt of late-night talk show jokes, the obesity epidemic has serious implications for public policy. If current trends hold, the state could face enormous increases in the already significant costs of treating diabetes, heart disease and other ailments caused by the extra poundage.