All it takes is one taste to notice the difference between Coca-Cola Zero Sugar and Diet Coke. Even though both are sugar-free versions of Coca-Cola, the formulations are distinct and offer different flavor profiles. Coca-Cola Zero Sugar uses the same flavorings as regular Coca-Cola, and is sweetened with aspartame and acesulfame potassium. Diet Coke only uses aspartame. As a result, the zero sugar version tastes more like the original sugar-sweetened kind.