Companies including PepsiCo are introducing beverages made with sugar instead of high-fructose corn syrup. The "Throwback" versions of Pepsi and Mountain Dew could signal a resurgence of sugar in the marketplace, some observers predict. Scientists, however, say there's no health benefit to the switch. "The idea of substituting sugar for high-fructose corn syrup is simply a marketing decision," one expert says. "There's no science to substantiate it."