Over a decade ago, Dr. Carlos Monteiro, a professor of nutrition and public health at the University of São Paulo and a nutritional epidemiologist, developed the NOVA classification for food. Under the system, foods are placed into one of four categories, ranging from unprocessed foods — like fresh fruits, vegetables, and meats — to ultra-processed foods (UPFs) that contain additives, flavorings, colorings, and sweeteners like high-fructose corn syrup. 

After literally defining UPFs and studying the effects of diets high in UPFs, Dr. Monteiro recommends that UPFs be labeled with warning labels, similar to those on cigarette packages. He also advocates for public health campaigns that would warn the public about the potential dangers of excess UPF consumption. 

“UPFs are increasing their share in and domination of global diets, despite the risk they represent to health in terms of increasing the risk of multiple chronic diseases,” Montiero told The Guardian. “UPFs are displacing healthier, less processed foods all over the world, and also causing a deterioration in diet quality due to their several harmful attributes. Together, these foods are driving the pandemic of obesity and other diet-related chronic diseases, such as diabetes.”

Monteiro presented his findings—and his proposed warning label—at the International Congress on Obesity, which was held in São Paulo last week. He also proposed banning the sales of UPFs in schools and healthcare facilities, suggesting that UPFs should be taxed more heavily than fresher, less-processed options. 

His concerns about the prevalence of UPFs aren’t unwarranted. 

According to the New York Times, UPFs account for over two-thirds (67%) of the total calories that U.S. children and teenagers consume. Earlier this year, a study published in The BMJ suggested that those whose diets are high in UPFs are at an increased risk for 32 different mental and physical health conditions. 

Although the concept of placing warning labels on UPFs hasn’t gone global yet, several countries in Latin America, including Argentina, Colombia, Peru, and Mexico, require warning labels on UPF packaging. The warnings, which are black octagons, alert the consumer that these products contain either excess calories, total fats, saturated fat, sodium, or sugar. 

Not everyone is convinced that warning labels are the right way to address the ubiquity of UPFs. Dr. Hilda Mulrooney, a registered dietitian and nutritionist and visiting senior fellow at London’s Kingston University, says that it’s “very simplistic”  to compare foods — even UPFs — and cigarettes. “There is no such thing as a safe cigarette, even second-hand, so banning them is relatively straightforward in that the health case is very clear,” she told The Guardian.