Diet Coke is one of the most popular sodas, and there’s a lot of confusion about whether it’s actually healthier than regular Coke due to the lack of sugar. Most consumers don’t consider Diet Coke to be healthy, but many wonder if it’s actually bad for you.
Does Diet Coke contain ingredients proven in medical studies to be bad for you? Is it a healthier or less healthy option than regular Coke? How does it compare to other soda brands? And can too much of it negatively affect the brain?
In this article we’ll answer all of these questions and more as we review the ingredients in Diet Coke based on clinical studies to give our take on whether or not it’s bad for you. We’ll share some surprising research on how Diet Coke may affect the brain, and explain if there are healthy diet soda drinks.
Does Diet Coke Contain Harmful Ingredients?
Diet Coke is primarily sweetened with aspartame which is an artificial sweetener. A medical review published in the Nutrients journal documented some potential safety concerns about the substance. The breakdown of aspartame by the body results in formaldehyde which “may damage DNA,” and one liter of diet soda results in around 60 milligrams (mg) of formaldehyde, which is 400 times the acceptable daily intake (ADI) level.
Potassium benzoate is a synthetic preservative which has been shown in a clinical trial to be clastogenic (DNA-damaging), mutagenic (potential for genetic mutation) and cytotoxic (toxic to living cells) to human cells.
Citric acid is a flavor enhancer typically derived from a fungus, and is associated with whole-body inflammatory reactions in a small subset of patients, as we documented in our recent review on “is coffee bad for you”.
Natural flavors is a broad category descriptor that fails to identify the specific flavoring agents used. There are documented toxicity concerns with some flavoring agents.
Phosphoric acid is a flavor enhancer associated with hypocalcemia (low blood calcium levels) in a medical review. Women who consumed one or more soda drinks with phosphoric acid were 28% more likely to have low blood calcium levels, which can lead to osteoporosis if not treated.
Healthiness is subjective, but overall we consider Diet Coke to be bad for you given the number of questionable additive ingredients that are associated with negative health outcomes in clinical research.
Is Diet Soda Bad for the Body and Brain?
An interesting, animated video published by Science Insider examined whether diet soda intake could be harmful to the body and brain. The video is only three minutes long:
Is Regular Coke Healthier?
The ingredients in regular Coke are shown above.
Both products contain phosphoric acid and natural flavors which we recommend avoiding. The key difference is that Coke is sweetened with high fructose corn syrup, which we consider to be an even less healthy sweetener than aspartame or cane sugar.
High fructose corn syrup has been extensively studied in medical trials, and is one of the processed food ingredients that's most highly associated with obesity. A Cleveland Clinic review found that high fructose corn syrup “promotes obesity more than regular sugar.”
A meta-study published in the PLOS One journal found that high fructose corn syrup can induce metabolic dysregulation.
Even though the beverage contains more questionable additives like a preservative and citric acid, we consider Diet Coke a healthier option than regular Coke just because of how much research suggests that high fructose corn syrup should be avoided. Diet Coke is also zero-calorie, which may make it a better option for overweight and obese individuals, given that regular Coke provides 140 calories and 39 grams (g) of added sugar in a 12 ounce can.
Our Healthy Soda Recommendation
While we don’t recommend drinking soda overall and would recommend replacing it with water, tea or coffee, for consumers who are set on drinking soda we consider Poppi Sparkling Prebiotic Soda to be a much healthier alternative to Diet Coke.
Poppi is sweetened naturally with organic cane sugar and juices like raspberry juice and strawberry juice. It only provides 20 calories and 4 g added sugar per can (10% of that in a regular Coke), and contains apple cider vinegar which is shown in medical research to have a favorable effect on cholesterol and blood sugar levels.
We would prefer to recommend a healthy soda brand without any added sugar at all, and without natural flavors, but for the time being this is the healthiest option we can locate. We definitely consider it to be a healthier option than Coke and Diet Coke. Poppi is free of artificial sweeteners, free of citric acid, and free of preservatives.
Interested consumers can check out Poppi Sparkling Prebiotic Soda at this link to the product’s Amazon listing.