At first glance, no one would blame you for thinking that Diet Coke and Coke Zero were the exact same drink in different packaging – after all, both offer consumers a sugar/calorie free alternative to the original Coke recipe.

Sure, marketing comes into play with the silver branded Diet Coke aimed mostly toward figure-conscious women, while the other provides men with a 'manly' excuse for their sugar-free choice.

But once we get past the outdated mind games, the formula is basically the same, right?

I still don't know the damn difference between Diet Coke and Coke Zero

— Tylor Fontenot (@tcf011) July 29, 2017

Wrong.

Any seasoned Coke drinker will tell you that these two products taste completely different, though no one could ever figure out why.

Well, it seems the mystery has finally been solved and the answer comes down to one simple ingredient – citric acid.

Commonly known as lemon salt, the preservative is exclusively used in Diet Coke, said to give the drink its unique 'tart-taste.'

Meanwhile, Coke Zero uses sodium citrate – an ingredient meant to mimic the taste of its full-fat counterpart.

Mystery solved.