Diet Coke is the go-to zero calorie soda — but rival fizzy drink is climbing in popularity

Coke Zero Sugar is gaining ground on Diet Coke, challenging a long-standing favourite among people choosing sugar-free fizzy drinks. The shift matters to consumers and sellers because the two drinks are often treated as substitutes, yet their flavours and loyal followings differ.

Coke Zero Sugar accounted for 52 per cent of soft drink sales growth last year, while Diet Coke sales have been largely flat since peaking around 2006. In an informal newsroom blind taste test, some participants identified the drinks correctly, but others could not; Coca-Cola says both are sugar-free but have different flavour profiles.