Tim Walz and JD Vance both love Diet Mountain Dew. But is it healthy?

Last month, Vance told a joke that fell flat about drinking the bubbly beverage (and was later ribbed over it by Kentucky Gov. Andy Beshear), and toasted with it at a public appearance with Newsmax, reportedly declaring, “This is the good stuff here. High-caffeine, low-calorie.”

Walz, meanwhile, demonstrated years ago that “a seemingly bottomless can of” the fizzy stuff was his refreshment of choice, according to a local profile, as was pointed out by the New York Times on Tuesday in a short piece about this “bizarre twist of beverage fate.” He’s also offered recent evidence of his love for the stuff on X.

News of the amusing common denominator comes about a year after the World Health Organization raised concerns about the health risks of aspartame, which is one of three artificial sweeteners—along with acesulfame potassium and sucralose—used in Diet Mountain Dew. And it comes several months after the Federal Trade Commission issued a warning to the American Beverage Association and the Canadian Sugar Institute for allegedly compensating dietician influencers to endorse the safety of aspartame on TikTok and Instagram without disclosing their connection to the trade associations.

Artificial sweeteners and Diet Mountain Dew

The FDA considers all three of the sweeteners to be “generally recognized as safe,” but manufacturers don’t need to present significant, peer-reviewed research in order to get a food additive into that category, Dr. Dariush Mozaffarian, MD, DrPH, a cardiologist and director of the Food Is Medicine Institute at the Friedman School of Nutrition Science and Policy at Tufts University, previously told Fortune.

It also didn’t stop the WHO’s International Agency for Research on Cancer (IARC) from classifying the artificial sweetener as “possibly carcinogenic to humans,” or level 2B out of four, and calling for more research.

“The assessments of aspartame have indicated that, while safety is not a major concern at the doses which are commonly used, potential effects have been described that need to be investigated by more and better studies,” noted the WHO’s director of the Department of Nutrition of Food Safety, Dr. Francesco Branca, at the time. 

“The Group 2B classification is the third-highest out of 4 levels,” explained the American Cancer Society, citing WHO’s evidence, “and it is generally used either when there is limited, but not convincing, evidence for cancer in humans, or when there is convincing evidence for cancer in lab animals, but not both.” 

To put it in perspective, a person weighing 150 pounds would have to consume about nine to 14 cans of diet soda a day to reach unsafe amounts, according to the FDA. 

Aspartame, though, is just one of the diet soda’s 16 ingredients, according to the nutrition label on the site of parent company PepsiCo—a spokesperson for which told Fortune it had “no comment” when reached to respond to questions about the health of its product. 

Are Diet Mountain Dew’s other ingredients bad for you?

The full ingredient list is as follows: “carbonated water, concentrated orange juice, citric acid, natural flavor, potassium benzoate (preserves freshness), citrus pectin, aspartame, potassium citrate, caffeine, sodium citrate, acesulfame potassium, sucralose, gum arabic, sodium benzoate (preserves freshness), calcium disodium EDTA (to protect flavor), yellow 5.” 

That complex, chartreuse combo has earned the product a food score of six out of 10 (10 being most hazardous) on the Environmental Working Group (EWG) consumer site, with the most potentially risky ingredients being the artificial color yellow 5, the nonspecific chemical mix of “natural flavor,” and aspartame, according to the site.

“It doesn’t score well because there’s ingredient concerns, there’s processing concerns, and there’s obviously not really much nutritional value in Diet Mountain Dew,” EWG’s senior scientist Tasha Stoiber tells Fortune. 

Besides aspartame, ingredients flagged by Stoiber include yellow 5, natural flavor, and the artificial sweeteners sucralose and acesulfame potassium.

“There was a recent study on links to cardiovascular disease that included these three sweeteners,” Stoiber says, pointing to the 2023 observational study which found an association between aspartame and stroke, and between acesulfame potassium and sucralose with higher coronary artery disease risk. 

The artificial color of yellow 5, otherwise known as tatrazine, meanwhile, has been flagged, she says, “especially for young children,” because of “numerous epidemiological studies” showing an association with behavioral changes including irritability, restlessness, depression and difficulty with sleeping. The EWG has sponsored legislation in California, still pending, that would call for removing articial dyes from foods eaten by kids in schools. But both the FDA and the European Food Safety Authority (EFSA) have deemed yellow 5 safe. 

Natural flavors, according to EWG, can actually contain synthetic chemicals, and safety evaluations may not be completely thorough.

Other controversial ingredients include the preservative calcium disodium EDTA, a slightly salty powder that’s been found to be related to digestive issues if consumed in very high amounts; and the additive sodium benzoate, which has been associated (without evidence of cause and effect), through various studies, with children’s hyperactivity, increased anxiety, hormone level disruption, and disrupted liver and kidney function, according to a 2022 study published in Nutrients. (But it’s not officially regarded as harmful—and has even shown therapeutic potential for treating depression, schizophrenia, autism spectrum disorder, and neurodegenerative diseases, according to that same study.) 

Finally, a 12-oz. serving of Diet Mountain Dew contains 54 milligrams of caffeine, compared to about 130 milligrams in the same size cup of coffee.  

It’s why drinking sodas either with sugar or artificial sweeteners is “a poor role model for the young whose habits are forming,” according to Alice H. Lichtenstein, professor of nutrition science and senior scientist at the Tufts University Jean Mayer USDA Human Nutrition Research Center on Aging. “It is better to never start drinking sweetened beverages than to have to shift away from them.”

So what about the thirsts of Walz and Vance?

“One of the best things that you can do for your health and energy levels is to stay hydrated,” suggests Stoiber. “And drinking filtered water is a great way to do that.”