Two World Health Organization reports expected later this week on the artificial sweetener aspartame could cause marketing headaches for hundreds of food and beverage products.

The sweetener, which was approved by the U.S. Food and Drug Administration in 1974, is an ingredient in many low-sugar or sugar-free products, including sugar-free gum such as Trident, sugar-free Jell-O, drink mix Crystal Light and Diet Coke and Diet Pepsi. 

One report is expected to label aspartame as “possibly carcinogenic” and the other will review the daily limit and long-term effects of consuming the sweetener. The pending rulings, first reported by Reuters in late June, have put new scrutiny on diet sodas, reigniting debate about their use of aspartame. Experts say big brands such as Diet Coke can withstand the negative news because of their loyal fan bases. Still, the reports could open the door for challenger soda brands that have made gains in recent years by touting healthier ingredients.

“This is more of an opportunity for other brands than a detriment to brands whose products contain aspartame,” said Kate Weidner, co-founder and CEO of SRW Agency, which works with natural food brands. “It’s not enough for them to read that Diet Coke is not good for you. You probably already knew that. So if you want to change my behavior, it has to be just as easy. Look at a ‘better for you’ soda. It might be more expensive, but an easy swap.”

Coca-Cola Co. and PepsiCo did not respond to requests for comment.

“I think the public cares about the report, but will it change behavior? I highly doubt it,” Peggy E. Stover, associate professor of practice and director at the University of Iowa’s Tippie College of Business Marketing Institute, wrote in an email. “People who are avid diet soda drinkers will continue to be loyal to their product. Getting a person to break a habit is extremely difficult. I doubt the industry will see a wave of diet soda loyalists suddenly switch to an alternative.”

While it is conceivable that Coke and Pepsi could tweak their diet drink formulas to remove aspartame, that is easier said than done, considering consumer taste preferences. Indeed, in 2015, PepsiCo removed aspartame from Diet Pepsi amid health concerns, but then brought it back a year later as a “classic sweetener blend” to appease loyalists clamoring for the old formula. Today, Pepsi sells Diet Pepsi and Pepsi Zero Sugar, both of which contain aspartame. Coca-Cola used to sell Coca-Cola Life, which was sweetened with sugar and stevia, not aspartame, but it was recently discontinued in the U.S.

With aspartame under fresh scrutiny, beverage giants could re-examine their product pipelines or even buy start-ups that focus on non-aspartame options. Coca-Cola, for instance, has begun testing a version of Diet Coke marketed as having “plant-based sweeteners'' (monk fruit and stevia extracts), according to Beverage Digest, which reported in April that the versions were being sold at retailers including Target stores in Minneapolis–Saint Paul.

“People are so loyal to products and the type of sweetener they prefer,” said Keith Niedermeier, a clinical professor of marketing at the Kelley School of Business at Indiana University. “I don’t think [the reports] will impact hardcore loyalists. But this could be an opportunity for these companies to speak to customers who are concerned by focusing on natural or no sweetener alternatives.”

Some natural food brands are already benefiting from the consumer shift to healthier options that accelerated during the pandemic, according to SRW's Weidner. She pointed to larger companies buying up smaller challenger brands in the wellness category. Nestlé purchased collagen maker Vital Proteins in 2022, Barilla acquired cookie brand Back to Nature in January and Unilever is set to buy Yasso, a frozen Greek yogurt dessert brand, later this year.

The aspartame rulings could give challenger drink brands a chance to sway consumers who are not die-hard diet soda fans but care about ingredients. According to Weidner, health and wellness brands try to attract new customers at the start of the new year (to help with resolutions), the start of the summer and then back to school. The report could add an extra acquisition window.

Niedermeier agreed. “If I were, say, La Croix, maybe this is a chance to be more aggressive in marketing.”

And anecdotally, younger generations seem to be opting for healthier hydration options.

“I’m in my 25th year of teaching,” said Niedermeier. “The classroom was full of Coke and Diet Coke 25 years ago. But now it shows up very little among university students. It’s water, iced coffee, or another alternative drink.”

Plus, shoppers won’t find Diet Coke at Whole Foods—it does not allow products containing aspartame. But Whole Foods does sell start-up beverages such as Olipop, a low-sugar, low-calorie soda that has disrupted the category with TikTok marketing and partnerships with the likes of Camila Cabello, an investor. 

Read more: How Olipop is disrupting the soda category

But classic diet sodas still command big followings. Diet Coke finished 2022 as the fifth-largest carbonated beverage according to Beverage Digest, with a 6.2% volume share, although its sales volume declined by 3.5%. The top slot in 2022 went to Coke, followed by Pepsi, Dr Pepper and Sprite. Coca-Cola has shifted more marketing resources behind Coke Zero Sugar (whose sweetener mix includes aspartame and acesulfame potassium) after rebranding and reformulating it in 2021. While the company put $2.6 million in measured media behind Diet Coke last year, Coke Zero got $57.8 million, according to Vivvix, including paid social data from Pathmatics.

One way for beverage companies to respond to the aspartame news is to highlight other existing products—including those that contain sugar. Niedermeier pointed to Mexican Coke, which has gained popularity for its use of cane sugar instead of high fructose corn syrup. (Coca-Cola also does this around Passover in the U.S.—look for the bottles with a yellow cap.) 

Weidner advised shifting marketing messages to focus on balanced consumption and a healthy lifestyle. 

“Anyone consuming aspartame is seeking wellness in some form,” said Weidner. “They are trying to be healthy. So what consumers will seek is permission. They don’t want to change their behavior, but brands will need to show them what a healthy lifestyle looks like, and how their product fits in.” 

How did we get here?

Aspartame is an artificial sweetener that is 200 times sweeter than regular table sugar. It was approved by the FDA in 1974 for use as a sweetener in gum, cereal, instant coffee and tea, puddings and dairy products. In 1996, the FDA approved aspartame as a general-purpose sweetener. 

The FDA’s acceptable daily intake for aspartame is 50 milligrams per kilogram of body weight. For context, that means a 150-pound person could safely consume roughly 3,400 milligrams a day. A 12-ounce can of diet soda typically contains around 200 milligrams of aspartame. So a 150-pound person would have to drink 17 cans of Diet Coke to reach the daily limit. Put another way, a 150-pound person would have to eat nearly 80 packets of Equal sweetener.

One of the new aspartame rulings will come from the International Agency for Research on Cancer (IARC), which is the World Health Organization’s cancer research arm. The IARC sorts materials and ingredients into four categories: carcinogenic (which includes burning coal and consuming opium), probably carcinogenic (eating red meat), possibly carcinogenic (where aspartame is anticipated to fall; includes gasoline exhaust and working with dry cleaning) and not classifiable as carcinogenic (chlorinated drinking water and hair coloring products). IARC will classify aspartame as possibly carcinogenic, according to Reuters.

The Joint FAO/WHO Expert Committee on Food Additives (JECFA), the WHO’s committee on additives, is also reviewing aspartame use. It will announce its findings on July 14, the same day that the IARC makes its decision. The two different reports complement each other. IARC assessed the potential carcinogenic effect of aspartame, while JECFA will update its risk assessment of the additive, including reviewing the acceptable daily intake and the effects of long-term aspartame intake.

But the FDA doesn’t necessarily have to take up the rulings. In fact, last year the FDA sent a letter to the WHO urging it to only have JECFA review aspartame, worried that IARC’s findings would confuse customers.

The American Beverage Association—a trade group whose members include Coca-Cola Co., PepsiCo, and Keurig Dr Pepper— was also recently critical of the IARC findings, pointing out that IARC is not a food safety agency, and that JECFA is more suited to assess any aspartame risks. The association also created a dedicated website filled with data that positions aspartame as safe to consume.

“Now it depends on the JECFA finding and how it’s received in the court of public opinion,” said Dr. Peter Lurie, president of the Center for Science in the Public Interest, a non-profit that advocates for safer and healthier foods. “If it's a clean bill of health, either on par or less than what IARC found, that would be a green light as far as big companies are concerned.”

But he said if JEFCA’s findings are more impactful—for example, if they show that aspartame is linked to another health issue—companies might opt to swap aspartame for another sweetener.