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Is Coke Zero Keto-Friendly?

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  Published on January 10th, 2022
  Reading time: 3 minutes
  Last modified July 9th, 2023
is coke zero keto

No matter what diet you are following, it is typically advised that you cut out soda. Soda is filled with sugar and calories–both of which aren’t beneficial when trying to lose weight or get healthy. Diet soda was created as a 0-calorie, sugar-free alternative to traditional soda, but in recent years it’s received a lot of backlash. There seems to be mixed information out there about whether or not Coke Zero is actually keto or not, but why?

Coke Zero Nutrition & Ingredients

Like Diet Coke, which is sweetened with aspartame, Coke Zero is sweetened with aspartame and acesulfame potassium (ace K). Coke Zero Sugar, a different sugar-free alternative, also contains aspartame as a primary sweetening agent. 

All three variations of zero calories Coca-Cola products contain 0 calories, 0g carbohydrates, and 0g of sugar. 

The Aspartame Controversy 

Aspartame is an artificial sweetener created from the two amino acids phenylalanine and aspartic acid. Because it is significantly sweetener than sugar, it is often used in diet products like diet soda as a zero-calorie, zero-sugar alternative. There are a few different problems that are associated with aspartame–the first being cancer.

Sugar-free diet soda in a glass

This idea that aspartame can cause cancer was due to a published paper that indicated a correlation between aspartame consumption and cancer in rats. [1] This study, however, has been called into question many times. For starters, animal studies do not correspond well to effects in humans. No consistent data in humans have been published indicating that aspartame is linked to cancer. Additionally, the rats were fed doses of aspartame high enough to be considered unsafe in humans. This isn’t exactly equivalent to having a diet drink every once and a while. [2]

Aspartame is an FDA-regulated food product. Its consumption is considered safe up to 50 mg/kg body weight per day. The European Union has a slightly lower safety measure at 40 mg/kg per day. To put that in perspective, if an individual weighs 150 lbs (68kg), up to 3,400mg of aspartame consumption per day is recognized as safe. Coke zero contains 58mg of aspartame per 8oz. That means in order to consume an unsafe amount of aspartame, that 150lb individual would have to consume about 58.6 8oz bottles of Coke Zero which is equivalent to 469 oz of the beverage. That’s a lot of diet soda! 

Additional Concerns About Aspartame

Other than cancer, there have been a few additional concerns regarding aspartame. Some research has identified a potential link between aspartame consumption and sweet cravings, as well as alterations in the gut microbiome. For more information on this research and additional concerns regarding aspartame, check out our full article about aspartame

Concluding Thoughts on Drinking Coke Zero on Keto

Drinking Coke Zero on a keto diet isn’t likely to kick you out of ketosis. If it helps curb sweet cravings and prevents you from drinking regular coke, then give it a shot. However, if you find that you do have increased cravings for sweets or other carbohydrates after drinking them, consider limiting consumption. At the end of the day, the healthiest thing you can drink is water, so don’t allow Coke Zero to be a substitution.

But, having a glass every once in a while is unlikely to cause any concern, unless you have been diagnosed with a specific condition like Phenylketonuria (PKU) which is a rare disorder resulting in the build-up of an amino acid called phenylalanine.

At ketogenic.com, we are committed to supporting, inspiring, and educating people on the benefits of living a ketogenic lifestyle. We do this by bringing together the top researchers, practitioners, and thought-leaders who provide resources, experience, and awareness associated around the Ketogenic diet. Utilizing the latest cutting-edge research along with practical experience, the team at ketogenic.com aims to foster awareness, understanding, and connectedness in helping others optimize their life on a ketogenic diet.



Schubert, C. Aspartame linked to increased cancer risk in rats. Nature (2005). https://doi.org/10.1038/news051114-15


Haighton L, Roberts A, Jonaitis T, Lynch B. Evaluation of aspartame cancer epidemiology studies based on quality appraisal criteria. Regul Toxicol Pharmacol. 2019 Apr;103:352-362. doi: 10.1016/j.yrtph.2019.01.033. Epub 2019 Feb 2. PMID: 30716379.

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