Diet Coke
Diet Coke does not use a modified form of the Coca-Cola recipe, but instead an entirely different formula. The controversial New Coke, introduced in 1985, used a version of the Diet Coke recipe that contained high fructose corn syrup and had a slightly different balance of ingredients. In 2004, Coca-Cola introduced Coca-Cola C2, which it claims tastes much closer to Coca-Cola but contains half the carbohydrates. In 2005, the company introduced Coca-Cola Zero (replaced by "Coca-Cola Zero Sugar" in 2017), a sugar-free variation of regular Coca-Cola.
Diet Coke
Diet Coke was sweetened with aspartame, an artificial sweetener, after the sweetener became available in the United States in 1983. Early on, to save money, this was also originally in a blend with saccharin. After Diet Rite cola advertised its 100 percent use of aspartame, and the manufacturer of NutraSweet (then G. D. Searle & Company) warned that the NutraSweet trademark would not be made available to a blend of sweeteners, Coca-Cola switched the formula to 100 percent NutraSweet. Diet Coke from fountain dispensers still contains some saccharin to extend shelf life.