Tab was Coca-Cola’s first nationally advertised diet cola, launched in 1963.
Coca-Cola introduced Tab in the United States as a low-calorie soft drink aimed at consumers who wanted a cola-style beverage with fewer calories. The name was chosen during the company’s search for a short, memorable brand identity. Tab originally used cyclamate and saccharin as sweeteners, and its formula changed after regulatory restrictions on cyclamate.
Tab predates Diet Coke by nearly two decades. Diet Coke was launched in 1982 and became a much larger global brand, while Tab developed a dedicated following among some consumers. Coca-Cola discontinued Tab in the United States in 2020 as part of a portfolio reduction.
Fresca was also a low-calorie Coca-Cola product, but it was introduced as a citrus-flavored soft drink rather than a cola. Coke Zero and Diet Coke came later, so neither is the answer to this historical question.