1960s Diet Pepsi

While I was searing about 1960s food I found Diet Pepsi was produced in 1960s that made me to be surprised.  

Diet Pepsi is a no-calorie carbonated cola soft drink produced by PepsiCo, introduced in 1964 as a variant of Pepsi-Cola with no sugar. First test marketed in 1963 under the name Patio Diet Cola, it was re-branded as Diet Pepsi the following year, becoming the first diet cola to be distributed on a national scale in the United States. 

References:

http://www.diamondcokecans.com/pepsicola.htm