Pepsi introduced Diet Pepsi as a nationwide product in 1964.
Diet Pepsi grew from the expanding market for low-calorie soft drinks. Pepsi-Cola introduced the drink in the United States as a sugar-free alternative, using the company’s familiar Pepsi branding while targeting consumers interested in reducing calorie intake. It became the first diet soft drink to be distributed nationally under the Pepsi name.
The product’s launch followed earlier experiments and regional diet beverages, including Patio Diet Cola. Diet Pepsi’s arrival gave Pepsi-Cola a major national competitor to Coca-Cola’s Tab, which had been introduced in 1963. Over time, Diet Pepsi’s formula, packaging and sweetener system changed several times.
Diet Pepsi is distinct from Pepsi Zero Sugar, which is marketed as a separate zero-sugar cola. The word “diet” in Diet Pepsi identifies its long-running brand positioning rather than a claim that every version has always used the same ingredients.