In the Seventh Arrondissement of Paris, there’s a perfect little restaurant that specializes in Burgundian food. I’ve been going there for 20 years, and nothing—the napkins, the menu, the stuffy bourgeois crowd—ever changes.
But on a recent visit, the dashing, snowy-haired gentleman at the neighboring table truly shocked me. “I’ll have the quenelles, poulet au vin jaune, a side of pommes vapeur, and, to drink, a Diet Coke,” he said, unwinding his foulard. “With ice.” The waiter didn’t even blink.
Diet Coke is trending far beyond TikTok and Instagram; as we launch into 2025, it may be the most discussed beverage on social media. First, there was the conversation around “marinating” and “pickling”—leaving it to chill in the fridge for weeks on end. Then there were the blind taste tests of “ice pairings.” (Crushed is the clear winner, with bonus points if it originates at a Regal Cinema.) And let’s not forget the “dirty soda” craze, in which, in the name of health, Diet Coke was mixed with a protein-rich vanilla shake (Fairlife Core Power, preferably).
Why now? Alcohol is looking less desirable all the time, but the group of teetotalers ordering Diet Coke instead of Côtes du Rhône is only part of the story. Since the drink’s launch, in 1982, savvy marketing has made it a very big business, and it’s never stopped growing. Its parent company, Coca-Cola, earned $43 billion in revenue in 2023, and in the United States, Diet Coke constitutes 7.8 percent of all soda consumed. (Regular Coke, with 35 grams of sugar—or nine teaspoons—in a 12-ounce can, leads the category with 19.2 percent.)
Coke, Pepsi, Sprite, Mountain Dew, Dr Pepper—that’s largely considered child’s play, rarely seen at adult dinner tables (or, God forbid, at dinner parties). But Diet Coke has fully transcended the snobbery that usually surrounds soda consumption. Karl Lagerfeld drank 10 glasses a day out of Lalique goblets. In 2022, the brand announced Kate Moss as its creative director. One of the world’s greatest chefs is even rumored to have had a serious Diet Coke habit—although he swears he no longer touches the stuff.
So what’s in this delicious chemical soup? Carbonated water, artificial coloring (Caramel E150d), “natural flavorings” (which could mean anything), the preservatives phosphoric and citric acids, caffeine (46 milligrams per 12-ounce can), and the artificial sweetener aspartame. (Coke Zero, popular with Europeans, contains the same ingredients and includes another artificial sweetener, acesulfame potassium. And it has 34 milligrams of caffeine.)
Diet Coke is widely considered to be one of the healthier types of soda, but still—is it even remotely “healthy”? First, its virtues: Because it’s artificially sweetened, it doesn’t cause the blood sugar to spike or increase one’s caloric intake. For those with diabetes, insulin resistance, or obesity, it’s a better choice than sugar-sweetened sodas.
Since the early 2000s, there have been concerns about possible links between aspartame and cancer, especially of the liver, but the evidence is limited. Today, the International Agency for Research on Cancer classifies aspartame as “possibly carcinogenic to humans,” and the Joint FAO/WHO Expert Committee on Food Additives declared that it does not pose a health concern. (It’s also used in sugar-free gums, diet-drink mixes, reduced-sugar condiments, and some yogurts.) If choosing between diet soda and anything containing alcohol, a known carcinogen, the consensus is clear: Diet Coke for the win.
But Diet Coke is no hero. Artificial sweeteners can still trigger sugar cravings and cause bloating, and in scientific communities, there’s increasing concern that they can harm the gut microbiome.
“When a lot of the safety testing was done, we didn’t really appreciate that we have these trillions of bacteria in our gut, and anything that reaches them and changes the types that live in there can impact our systemic health, whether it is things like blood-sugar regulation or heart health,” says Megan Rossi, a research fellow at King’s College London with a doctorate in gut health.
In one way, sugar may not be as evil as previously believed. “Our digestive tract is nine meters long, and most of the bacteria live in the last 1.5 meters,” says Rossi. “Sugar is absorbed so high up in the intestine that it doesn’t reach the microbiome.” The artificial sweeteners, however, make it all the way through the digestive tract. “Our bodies lack the enzymes to digest them,” says Rossi.
In 2022, a randomized controlled study on the effects of non-nutritive sweeteners in humans was published by scientists at Johns Hopkins University. It revealed that different sweeteners affect the gut microbiome in different ways, which can contribute to increased levels of inflammation.
“As a clinician and researcher, I’m very cautious around artificial sweeteners,” says Rossi. “Perhaps you can’t have your cake and eat it, too.”
Diet Coke’s caffeine content may also be problematic. The F.D.A. recommends no more than 400 milligrams a day, but a two-shot cappuccino followed by two cans of Diet Coke would likely exceed that level, potentially exacerbating anxiety, insomnia, and high blood pressure.
Phosphoric acid, an additive in most dark-colored sodas, used to enhance flavor, may be linked to tooth decay and bone de-mineralization. A recent study from scientists at Tufts University found that, in older women, high levels of cola intake were associated with lower levels of bone density.
The occasional can of Diet Coke won’t kill you, but there’s no reason to tempt fate and make like Lagerfeld. Rossi suggests gradually replacing Diet Coke with sparkling water, preferably poured over mixed berries. “They contain polyphenols, which feed your microbiome in a really positive and anti-inflammatory way,” she says. Let’s hope that, too, starts trending on TikTok.
Ashley Baker is the Executive Editor at Air Mail Look
