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.
New Coke
Market analysts believed baby boomers were more likely to purchase diet drinks as they aged and remained health- and weight-conscious. Growth in the full-calorie segment would have to come from younger drinkers, who at that time favored Pepsi by even more overwhelming margins than the market as a whole. Meanwhile, the overall market for colas steadily declined in the early 1980s, as consumers increasingly purchased diet and non-cola soft drinks, many of which were sold by Coca-Cola themselves. This trend further eroded Coca-Cola's market share. When Roberto Goizueta became Coca-Cola CEO in 1980, he pointedly told employees there would be no "sacred cows" in how the company did business, including how it formulated its drinks.