Diet Coke vs. Coke Zero: What Sets Them Apart?

For Coca-Cola enthusiasts looking to cut down on sugar, the debate between Diet Coke and Coke Zero is likely a familiar one.

Here’s a detailed comparison of these two popular beverages.

Ingredients

While the ingredients in Diet Coke and Coke Zero are nearly the same, there are subtle differences. Diet Coke's ingredients include:

In August 2017, Coke Zero underwent a rebranding, introducing a new formula and name: Coke Zero Sugar. Coke Zero Sugar's ingredients consist of:

Both Diet Coke and Coke Zero Sugar include phenylalanine. By examining their ingredient labels, we can uncover some interesting insights.

Carbonated Water and Caramel Color

The primary components of both Diet Coke and Coke Zero Sugar are carbonated water and caramel color, listed as the first and second ingredients. This indicates that both beverages are primarily made up of water infused with carbon dioxide and a coloring agent.

Artificial Sweeteners

Aspartame ranks as the third ingredient in Diet Coke and the fourth in Coke Zero Sugar, suggesting that Diet Coke may contain slightly more aspartame. Coke Zero Sugar, on the other hand, incorporates two artificial sweeteners: aspartame and acesulfame potassium.

Aspartame, an artificial sweetener, is up to 200 times sweeter than regular sugar. To experience its taste, try one of the small blue Equal packets available at most diners.

Phosphoric Acid

Phosphoric acid is listed as the fourth ingredient in Diet Coke and the third in Coke Zero Sugar, indicating that Coke Zero has a slightly higher concentration of this ingredient compared to Diet Coke.

As noted by Britannica, phosphoric acid "adds an acidic, fruity flavor to food products." Beyond its culinary uses, it is also employed in fertilizer production and water purification processes.

Potassium Benzoate

Potassium benzoate ranks as the fifth ingredient in both Diet Coke and Coke Zero Sugar. The National Library of Medicine describes it as "a fungistatic compound [which prevents the growth of fungi] commonly used as a preservative in food products."

On the ingredient labels of both beverages, potassium benzoate is noted for its role in "preserving the taste."

Natural Flavors

"Natural flavors" are listed as the sixth ingredient in both Diet Coke and Coke Zero.

According to the U.S. Food and Drug Administration (FDA), natural flavors are "obtained from spices, fruits, vegetables, herbs, or other plant or animal sources, primarily used to enhance flavor rather than provide nutritional value."

Natural flavors are derived from actual food sources through distillation or extraction, unlike artificial flavors, which are chemically created. While the exact composition of these natural flavors remains undisclosed, Coca-Cola characterizes the flavor of Diet Coke as a blend of "cherry and ginger lime."

Citric Acid vs. Potassium Citrate

Diet Coke includes citric acid as its sixth ingredient, whereas Coke Zero uses potassium citrate. Citric acid, found in citrus fruits like lemons and limes, is often used in home canning and jam-making. It likely contributes to the lime flavor in Diet Coke.

Potassium citrate, an alkalizing agent, reduces the acidity in soda, giving Coke Zero a smoother and more balanced taste compared to Diet Coke.

Caffeine

Both Coke Zero Sugar and Diet Coke include caffeine as their last ingredient. Caffeine, a natural stimulant with a bitter taste, is present in coffee, tea, and chocolate, and is often added to various beverages.

Caffeine promotes alertness by inhibiting the brain's adenosine receptors, which induce sleepiness. Diet Coke contains 46 milligrams of caffeine per 12 fluid ounces (355 milliliters), while Coke Zero Sugar has 34 milligrams in the same serving size.

For comparison, the FDA notes that an 8-ounce (237-milliliter) cup of black tea has 30 to 50 milligrams of caffeine, while the same amount of drip coffee contains 80 to 100 milligrams.

Nutrition Facts

The nutritional profiles of Diet Coke and Coke Zero Sugar are nearly identical.

Flavor

The variation in ingredients results in distinct flavor profiles for Diet Coke and Coke Zero Sugar.

The Coca-Cola Company characterizes Diet Coke's flavor as "bold cherry and ginger lime," while it states that Coke Zero Sugar "delivers the classic Coke taste without sugar or calories."

As per Coca-Cola Great Britain, "Coca‑Cola Zero Sugar closely resembles the original Coca‑Cola in appearance and taste, whereas Diet Coke features a unique flavor blend that results in a lighter taste."