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

A bitter rivalry is brewing across global office desks and pub tables, as Coke Zero Sugar threatens to dethrone Diet Coke as the nation’s favourite sugar-free fizz.For decades, Diet Coke has been a beloved staple of many people’s daily lives, from essential 3pm work pick-me-ups to a trusty low-calorie mixer on a Saturday night.It’s spanned multiple generations of loyal fans, with younger drinkers even rebranding the silver can as a modern “fridge cigarette” for anyone looking to blow off steam without reaching for nicotine.Yet in recent years, the drink’s younger sibling, Coke Zero Sugar, has quietly grown, accounting for a massive 52 per cent of soft drink sales growth last year.By comparison, Diet Coke sales have remained largely flat since peaking around 2006, creating a fierce cultural divide between diehard drinkers of both formulas.The great debateThe lingering question dividing Aussie consumers boiled over during a routine takeaway lunch run this week, when my order for a Coke Zero was met with the dreaded hospitality reply: “We only have Diet Coke.”That single interaction exposed an awkward truth: despite my intense brand loyalty to Coke Zero Sugar, I can’t actually pinpoint what separates the two drinks.To put the rivalry to the test, I staged a completely unscientific blind taste-test across the newsroom floor to see if other self-proclaimed soft drink connoisseurs could actually tell the drinks apart.Before taking a single sip, colleagues weighed in with wildly conflicting theories on what made each drink distinct.“I think Diet Coke tastes more metallic,” offered one colleague, Bucky.Another colleague, Gabi, was convinced the classic formula carried hidden carbs, asking: “Coke Zero has zero sugar, and Diet Coke has a little bit of sugar.”For Abisha, the supposed difference was purely psychological.“I think it’s a placebo and it’s not real, there’s no difference,” she argued.Heavy consumer Ben, who routinely drinks four ...