Is Coke Zero Bad For You? Coke Zero Sugar vs. Diet Coke.

Is Coke Zero Bad For You? Coke Zero Sugar vs. Diet Coke.

Quite often when people meet me and find out I’m a fitness coach and author, they jump to questions:

This is exactly what happened at a baby shower a couple of months ago. The Alzheimer’s-stroke study on diet soda had just come out and the hostess was dying to know what the deal is and whether her daily soda habit was something she should give up.

She said she loved it and did not want to stop it but her husband was nagging her hard about it. So today we’re going to answer this question – is coke zero bad for you?

I invited Ana Reisdorf, an RD, to tackle the question. Enter Ana:


You may have heard people talking about the dangers of fake sugar in diet soda, particularly aspartame. Does this mean you need to avoid diet soda drinks completely because they’re terribly unhealthy as a beverage choice?

We’ll start out by going over the ingredients in Coke Zero (now renamed to Coke Zero Sugar) and then discussing common concerns relating to it, like:

  • Do artificial sweeteners in Coke Zero cause Alzheimer’s or stroke?
  • Does Coke Zero make you fat?

What’s in Coke Zero Sugar anyway?

Coke Zero Sugar, formerly known as Coke Zero, is a no calorie, no sugar beverage from the Coca Cola company. It was rebranded into Coke Zero Sugar in August of 2017. The company states that the new name also comes with a new look and a more delicious taste.

The appeal of Coke Zero Sugar has always been that it tastes more like real coke than Diet Coke does, without the “fake” sugar flavor of aspartame.

Ingredient Breakdown of Coke Zero Sugar

Coke Zero Sugar is similar to Diet Coke in that it contains zero calories and zero sugar. It comes in different varieties similar to regular Coca-Cola such as vanilla, caffeine-free, and cherry.

Looking at the nutrition label, it has a zero next to almost every nutrient.

  • It does have a small amount of potassium and sodium, but would not be considered a high source of either of these electrolytes.
  • The rest of the ingredients, caramel color, phosphoric acid, potassium benzoate, natural flavors, and potassium citrate are mostly preservatives, used to modify taste, or meant to add color to the beverage.
  • Coke Zero Sugar does contain some caffeine, about 34 mg per 12 ounce serving or about 25% of what you would find in an average 12 ounce cup of coffee.

Coke Zero Sugar, as the name suggests, includes no sugar but is instead sweetened with artificial sweeteners – which brings us to the new section.

Artificial sweeteners in Coke Zero

Coke Zero Sugar is sweetened with a combination of two artificial sweeteners, aspartame and acesulfame K. Diet Coke only has aspartame as the primary sweetener, whereas original Coca-Cola is sweetened with high fructose corn syrup. Coke Zero Sugar has less aspartame than Diet Coke, which is likely why the taste is more similar to original Coca-Cola without the added sugar.

Sugar Substitutes: Coke Zero vs Diet Coke vs Regular Coke.

Artificial sweeteners and “diet” beverages have been a hot topic of debate in the nutrition community since they came on the market.

  • How can something that tastes sweet have no calories and therefore no consequences to your health?
  • Are artificially sweetened beverages a better choice than “regular” soft drinks?

To be honest, while the research on the long-term effects of these beverages is conflicting, there have been some new studies on their effect on brain health and weight that may shed some light on this hotly debated topic.

Is acesulfame potassium safer than aspartame?

As I said before the main difference between Diet Coke and Coke Zero is that Coke Zero is sweetened with both aspartame and ACE-K while Diet Coke only includes aspartame.

diet coke aspartame

But while aspartame is pretty famous, you are likely not as familiar with acesulfame potassium (ACE-K) as you might be with aspartame. ACE-K was discovered in 1967 and has become a popular sugar substitute in many foods. It is generally blended with aspartame or other sweeteners because it has a bitter taste on its own.

ACE-K is considered safe for human consumption both in the United States and in Europe. The FDA has set the acceptable daily intake of this additive at 15 mg/kg/day of body weight. In order to exceed this limit, the average person would need to consume over 20 cans of Coke Zero Sugar in one day. It is unlikely that anyone is consistently drinking this much Coke Zero Sugar (1).

Yet, some believe there is not enough solid evidence to determine its long-term safety. There is some research that has found that ACE-K, like many artificial sweeteners, may interfere with appetite, possibly leading to weight gain and problems with blood sugar regulation.

Also, there are some concerns about it being a carcinogen and affecting the development of the fetus during pregnancy. At this time, there is not enough substantial evidence to determine with certainty that ACE-K is dangerous to long-term human health when consumed in normal doses (2).

Aspartame has been researched in great detail as well, yet it remains controversial. A 2013 review of evidence related to the safety of aspartame found that at levels below 40 mg/kg of body weight per day or the equivalent of 19 Diet Cokes daily, there was no danger in consuming aspartame. As long as it is not consumed in excess, 19 Diet Cokes per day is a lot, aspartame is considered safe.(3) The 40 mg/kg per day is the standard set by the European Union, the FDA sets it slightly higher at 50 mg/kg.

There are no studies comparing ACE-K to aspartame directly in terms of safety, so it is not possible to definitively say if one is safer than the other. The sweeteners in Diet Coke and Coke Zero Sugar are both considered safe in normally consumed doses by both the FDA and European Union.

Do artificial sweeteners cause Alzheimer’s or stroke?

A new 2017 study published in Stroke evaluated the connection between the intake of sugar and artificially-sweetened beverage on the risk of stroke and dementia. Researchers utilized data from the Framingham Heart Study Offspring in order to determine a correlation between consumption of artificially sweetened beverages and brain-related conditions (4).

The study included 2888 participants over the age of 45 who were questioned at various intervals over a 10 year period about their beverage consumption via a food frequency questionnaire.

After adjusting for confounding variables such as physical activity and smoking, researchers found that the intake of artificially sweetened beverages was associated with an increased risk for dementia, stroke, and Alzheimer’s disease (5). Similar results have been found with data from other large observational studies, such as the Nurse’s Health Study and the Northern Manhattan study.

Does this research mean you should throw out all the Coke Zero Sugar and switch immediately to regular Coke?

  • Not so fast because sugar sweetened beverages have also been associated with an increased risk of stroke.
  • Also, this research is all observational, meaning they follow a population group over a period of time to see what happens to their health while collecting information about their diet and lifestyle patterns.
  • These types of studies, although they can provide information on potential connections or correlations between two factors, do not prove causation.

One potential confounding variable in this study is that people already predisposed to stroke may have switched to diet beverages to lower their risk. Unfortunately, since many of the studies on artificial sweeteners and brain heath are correlational, therefore it is difficult to make a definitive recommendation on their safety.

Do artificial sweeteners make you fat?

Another concern many people have over the consumption of artificial sweeteners is if they make you gain weight. Once again the research is mixed on this topic.

  • On one hand there are several observational studies that suggest artificial sweeteners may increase cravings for high sugar foods due to the impact they have on appetite-regulating hormones, potentially leading to weight gain.
  • Others have found that artificial sweeteners may promote insulin resistance and inflammation, with the potential to lead to weight gain (6).

But, none of these connections have been proven to be a direct cause of weight gain (7).

A 2014 systematic review of the available evidence on artificial sweeteners and body weight looked at 24 different studies on this topic, which included a combination of randomized control trials and prospective cohort studies

The review found that the data from the randomized control trails, considered the “gold standard” for experimental studies, demonstrated that consumption of artificial sweeteners helped lower body weight, fat mass, and waist circumference. The cohort studies on average showed no connection between body weight and intake of artificial sweeteners (8).

With this meta-analysis of randomized control trials, we can likely conclude that intake of artificial sweeteners do not cause weight in any significant way and may even help with weight loss.

Researchers conclude that the overall reduction of sugar from the diet, even if you are replacing it with artificial sweeteners, helps reduce calories overall which helped study participants lose weight (9).

Is Coke Zero Sugar bad for you?

At the end of the day, is Coke Zero Sugar bad for you? The answer is probably not in moderation, even for brain health. Also, it is likely a better choice for those who want to manage their weight when compared to regular Coke or other sugar sweetened beverages.

Diet Coke is also not bad for your health, if once again it is consumed in moderation. Drinking DietCoke versus Coke Zero Sugar is likely equivalent in terms of the impact they may have on health.

Ideally, your beverage of choice should be water, but sometimes we crave a little something with a little more flavor, carbonation, or caffeine. Coke Zero Sugar or a Diet Coke can be a good option for a little mid-afternoon caffeine boost with no calories or sugar for those of us concerned about our weight, who also want a refreshing beverage from time to time.

ana reisdorf, dietitian

Ana Reisdorf is a Registered Dietitian Nutritionist and freelance writer with 10-years experience in the field of nutrition and dietetics. Currently, she works to share her passion for nutrition on a larger scale as an author. She has written for various online publications, such as The List, Today’s Dietitian, and Dr. Josh Axe.

Click here to view the sources referenced in this article.