Coke Zero vs. Diet Coke on Keto

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Written by Brenda Peralta, Registered Dietitian and medically reviewed by Abby Courtenay

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Often, people don’t know what to include when they start a ketogenic lifestyle. One of the most common questions is what you can drink that is keto-friendly. Sugar-free beverages are the top choice since they don’t contain any calories or added sugars.

Coca-Cola is one of the top brands people love. However, there are many different types of coke to choose from. Is there one better than the other when it comes to keto? What is the difference between Diet Coke versus Coke Zero? Which one is better for a low-carb diet?

In this article, you will learn everything related to these two popular beverages and how they relate to a ketogenic eating pattern.


Diet Coke vs. Coke Zero nutrition facts

Even though they come from the same brand, there might be differences between Coke Zero and Diet Coke. How many calories does each one have? What is the macro breakdown?

In the table below, you can find the nutritional information for 1 can of both products. They are based on the information given in the USDA FoodCentral Database website.

Nutrients Coke Zero (1 can) Diet Coke (1 can)
Energy 0 kcal 0 kcal
Fat 0 g 0 g
Protein 0 g 0 g
Net carbs 0 g 0 g
Total carbs 0 g 0 g
Fiber 0 g 0 g


As you can see, both have the same nutritional content. Neither of them has any calories, which means that they don’t offer any carbohydrates to your diet.

Additionally, the only micronutrient that they have is sodium. Both have 12 mg of sodium per 100 mL (and 1 can of soda contains 355 mL). This is not a significant amount if you drink it in moderation. However, remember that having a high-sodium diet can lead to high blood pressure.


Differences between Coke Zero and Diet Coke

When it comes to the nutritional value, they are the same. 

Does this mean that they are the same in everything else, or are there any differences? 

Although the differences are minimal, there are certain changes in their taste and ingredients.

The first difference comes with the sweeteners used in each one. In Diet Coke, the only sugar-free sweetener used is aspartame. Coke Zero uses aspartame and acesulfame k. Both of them are great options as non-caloric sweeteners. The reason why the formula differs is to offer two unique flavors.

The second difference between these two common beverages is taste. Diet Coke has a slightly different flavor than the original beverage (the one that contains all the added sugars). Hence, Coke Zero was created. It tastes the same as the original product, but without the calories and the added sugars.

Finally, the third difference between them is the caffeine content. One can of the diet version contains 46 mg of caffeine, while the zero version has only 34 mg. Although they have different caffeine intakes, it is still below the recommended amount of caffeine for a healthy adult, which is 400 mg per day.


When to drink Diet Coke or Coke Zero

When it comes to when to have each one, it depends on your preferences. If you like the taste of the diet version, then having this one might be the better option for you.

On the other hand, if you are missing the regular version but don’t want to have it with all the added sugars, you might opt for the zero version.

Did you know that one bottle (20 oz) of original Coca-Cola has 65 g of added sugars? This is the same as having 16 teaspoons of sugar in just one drink. This amount is too much for someone following a ketogenic lifestyle. It would easily kick you out of ketosis.


Which one is better for a ketogenic diet?

Both have 0 calories and 0 carbs. This means that you can have either one of them when doing a ketogenic diet. Neither will get you out of ketosis or affect your overall progress.

If you are looking to add something sweet without any added calories, both beverages are good to go.

However, keep in mind that they don’t offer any nutritional value. They don’t have any vitamins and minerals. Remember that variety is vital. While having a can once in a while is okay, it’s not exactly a healthy habit. Your main drink of choice should be water.



Either the Diet or the Zero type of Coca-Cola are great options to have when doing a ketogenic plan. They won’t contribute any calories or sugars that can disrupt your progress.

However, diet and sugar-free sodas don’t provide any nutritional value, which means that you need to add whole foods like fruits and veggies to ensure you are getting adequate nutrition.