The technical answer is that Diet Coke uses only aspartame as its sweetener, while Coke Zero uses a blend of aspartame and acesulfame potassium. The reason they both exist though is marketing: Coke Zero was created to appeal to a male demographic that considered “diet” drinks to be feminine.
The technical answer is that Diet Coke uses only aspartame as its sweetener, while Coke Zero uses a blend of…