What Is the Difference Between Diet Coke and Coke Zero?

If you’ve ever been at a party or perhaps work event with a particularly well-stocked soda fridge, you might have found yourself staring at both Diet Coke and Coke Zero and not been sure which one to choose. You stand there, with the silver can in one hand and the black can in the other hand, trying to make your decision, considering the disparate paths that your life will go down depending on what beverage you select. It’s a situation we find ourselves in all too often. Well, fear not, because I will explain to you the difference between Diet Coke and Coke Zero.

To tackle the topic of Coke Zero vs Diet Coke, let’s see what the back of the can has to say. According to the ingredients list, Diet Coke contains “carbonated water, caramel color, aspartame, phosphoric acid, potassium benzoate (to protect taste), natural flavors, citric acid, caffeine.” Meanwhile, Coke Zero contains “carbonated Water, caramel color, phosphoric acid, aspartame, potassium benzoate (to protect taste), natural flavors, potassium citrate, acesulfame potassium, caffeine.”

Eagle-eyed readers may have spotted the fact that these two ingredients lists are mighty similar. In fact, the only noteworthy difference is that Coke Zero contains potassium citrate and acesulfame potassium, while Diet Coke contains phosphoric acid. Other than that, they’re the same, ingredients-wise.

Another slight distinction between the two drinks is that Diet Coke has 46 milligrams of caffeine in a 12-oz can, while Coke Zero has 34 milligrams. However, both of these are well under the 95 milligrams found in a typical cup of coffee, so you’re not likely to notice the difference of 12 milligrams between the beverages.

(Incidentally, the ingredients of most diet colas are all quite similar to each other. For comparison, Diet Dr. Pepper has 45 milligrams of caffeine per can and its ingredients list consists of “carbonated water, caramel color, aspartame, phosphoric acid, natural and artificial flavors, sodium benzoate (preservative), caffeine.”)

So, what exactly are these differences in ingredients? Let’s delve a little deeper.

While Diet Coke uses just aspartame to provide sweetness in lieu of sugar, Coke Zero also uses the artificial sweetener acesulfame potassium. A cursory glance at the Wikipedia page for acesulfame potassium yields a couple of interesting nuggets such as the fact that it was invented in Germany in 1967 and is 200 times sweeter than sugar.

Diet Coke uses phosphoric acid to add a hint of tartness while Coke Zero uses potassium citrate to similar effect (unfortunately, no fun facts for either of these chemicals). So, when it comes to the formula, there’s very little difference between the two drinks. However, that doesn’t tell the full story about their differences. After all, humans share 99% of their DNA with chimpanzees.

The real distinction with Coke Zero vs Diet Coke comes down to taste. According to Coca-Cola’s website, “Coca-Cola Zero Sugar looks and tastes more like Coca-Cola Classic, while Diet Coke has a lighter taste because it’s made with a different blend of flavors—or has a different flavor base, as some might say.” That’s all well and good, but it sounds a little corporate—the same page also tells us, “We have a saying that there’s a Coca-Cola out there for everyone.” So, let’s see what the people have to say.

From speaking to a variety of Coke fans and conducting my own taste testing, it’s clear that there are few people who would argue that either calorie-free Coca-Cola variety quite tastes like the original thing. However, Coke Zero does taste closer for many, with a slightly sweeter flavor profile. 

Which one will you like better? Only one way to find out: As the marketing tells us, enjoy Coca-Cola!

About the Author

Matt Crowley

Matt Crowley is a comedy writer living in Los Angeles. He likes maple-flavored snacks, loves every kind of cheese, and is slowly learning to accept mushrooms.

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  • If you are prone to getting kidney stones, stay away from drinks containing phosphoric acid. I was so unhappy when soda companies switched citric acid with phosphoric acid. Had to give up drinking them. 😢

  • Diet Coke is based on New Coke, Coke Zero is based on Coke Classic. Coke does not like to remind people of “New” Coke so they conveniently skip that. Diet Coke replaced Tab.

  • When I was hospitalized with pancreatitis, the doctor placed a stent in my stomach to help the pancreatic fluid drain. The point of this disgusting comment? The doctor prescribed me Coke Zero to keep the stent open and draining. Apparently it had the highest acidity compared to other sodas. When I ordered a meal while hospitalized, I had to explain this whole story when I was told they don’t carry Coke Zero (apparently the gift shop did, even though the kitchen didn’t). I developed a real craving for Coke Zero after a while. I thought maybe Coke had some secret chemical in Coke Zero to make you crave it.

  • I enjoy Coke Zero much better than Diet Coke i think it tastes a lot better.

  • I hope the “new Coke Zero Move” goes away pretty quickly. I stated drinking Coke Zero about three years ago (getting away from regular coke) on the advise of a diabetic dietician. I’d lost 20 pounds in about 6 months. I now love the taste. My first swallow of Move nearly gagged me. I hope this trial end very quickly.