Rapidly falling sales have prompted PepsiCo to reformulate the diet version of its flagship product. Starting in August, all diet Pepsi varieties will no longer have aspartame, the widely unpopular artificial sweetner also known by the names Equal and NutraSweet. Pepsi vice president Seth Kaufman called it the "No. 1 reason consumers are dropping diet soda"—a likely claim since, at 22 percent, aspartame's popularity is even lower than that of Congress, according to one measurement.
