What's Actually Healthier—Diet Coke or Coke Zero?

Emily Laurence
·5 min read
27

Coca-Cola is the most popular soft drink not only in the U.S., but the entire world. However, it’s also a beverage option that's not recommended by doctors, dietitians and other health-focused experts. You can probably guess the major reason why. Yep, the sugar content. One can of Coke has 39 grams of sugar, which is more than what’s recommended to consume for the entire day.

That’s where Diet Coke and Coke Zero come in. Both drinks do not contain any calories or sugar. Instead, artificial sweeteners are used to make them taste good. While the drinks have this in common, there are ways they’re different from each other too. How do they compare when it comes to nutrition and how they affect the body? Below, registered dietitians give their honest thoughts about Coke Zero vs. Diet Coke. Here, find out everything you need to know about which sweet drink is best for your health.

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What’s in Diet Coke and Coke Zero—And How They Compare to Coke

Coca-Cola’s website says that Diet Coke is naturally flavored with cherry and ginger lime. However, looking at the ingredients list, it’s clear that not everything in the drink is all-natural. The ingredients in Diet Coke include carbonated water, caramel color, aspartame, phosphoric acid, potassium benzoate, natural flavors, citric acid and caffeine. Coke Zero has an almost identical ingredient list, except that it uses aspartame and acesulfame potassium as sweetening agents while Diet Coke just uses aspartame. Additionally, the flavors used in Coke Zero make it taste different than Diet Coke and it is also lower in caffeine.

Registered dietitian Andrea Mathis, MA, RDN, LD, says that the fact that both beverages are made with artificial ingredients instead of sugar does not make them healthier than Coke. “Artificial sweeteners do not make a beverage healthier. It just decreases the sugar and caloric intake, which may be beneficial to some individuals who are advised to monitor or limit their sugar or carbohydrate intake,” she says.

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Registered dietitian Christa Brown, RDN agrees with Mathis that Diet Coke and Coke Zero aren’t necessarily healthier than Coke; it depends on what someone’s individual health goals are. “While consuming sugary beverages in excess can contribute to weight gain, obesity and other health problems such as diabetes, consuming high amounts of artificial sweeteners has also been associated with some negative health effects,” she says. For example, Brown points to studies that have linked the consumption of artificial sweeteners with an increased risk of developing certain health conditions such as metabolic syndrome, Type 2 diabetes and heart disease.

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Coke Zero vs. Diet Coke: Which One Is the Healthier Choice?

As explained above, Diet Coke and Coke Zero use different sweetening agents. Both have aspartame, which Brown explains is a low-calorie sweetener made of two amino acids (phenylalanine and aspartic acid) and a small amount of methanol. In addition to aspartame, Coke Zero has acesulfame potassium. “It is a calorie-free sugar substitute that is commonly used in processed foods and drinks. It is often combined with other sweeteners, such as aspartame, to enhance its sweetness,” Brown says.

She explains that both aspartame and acesulfame potassium are not known to raise blood sugar levels, making them an attractive option for people with diabetes or those trying to manage their blood sugar levels. “Instead, they pass through the body largely undigested and are excreted in the urine without providing calories,” she says.

Even though they don't raise blood sugar levels, registered dietitian Jenny Beth Kroplin, RDN, LDN says that artificial sweeteners may cause the body to crave sweets. "Aspartame and acesulfame potassium don’t raise blood glucose levels however, the sweetness of artificial sweeteners may trigger the cephalic phase in the release of insulin and cause an increase in insulin levels in the body over time," she says.

All three dietitians say that the slight difference in artificial sweeteners used does not make one soda healthier than the other. This leads us to the other main difference: the caffeine content. As previously stated, Coke Zero is lower in caffeine than Diet Coke. Despite this difference, all three dietitians say that, once again, it does not make one healthier than the other. “The caffeine content doesn’t necessarily make a food or beverage healthier, but it can make it a better or worse choice for certain individuals depending on their lifestyle or health status,” Mathis says.

With all of this in mind, all three dietitians say that in the debate between Diet Coke and Coke Zero, it’s best to simply go with the one you like the taste of. And if you want to minimize your caffeine content, go for Coke Zero instead of Diet Coke.

However, the dietitians emphasize that it’s important to know that neither drink is healthy. What’s really best is minimizing your intake of soda in general, regardless of which one you like best. Mathis and Kroplin say to start by gradually decreasing the amount you drink, which can be more successful long-term than going cold turkey and giving up soda completely all at once. Brown says that drinking bubbly water with fruit can serve as a healthy replacement for soda when you’re craving something carbonated and sweet.

Brown explains that drinking the occasional Diet Coke or Coke Zero isn’t going to drastically impair your health; it’s okay to enjoy a soda once in a while. But if you’re drinking one every day, it’s worth it to think about how you can cut back. Have fun experimenting with different fruits you can add to bubbly water—it’s a way to enjoy natural flavors without artificial ingredients.

Next up, read an honest review of Poppi prebiotic soda and find out if it's really good for you.

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