The original Diet Coke. Tab was created because Coke execs in the 60s didn’t want the coke name on anything BUT Coke. A diet version was not considered a mainstream product back then. In 1982 Coca-Cola reformulated Tab and released this version as Diet Coke, although the original Tab formulation remained in the marketplace. In 1985 the relatively young Diet Coke formula was modified. Tab, however, has not changed its formula since its release in 1968.