Ultraprocessed food (UPF) has recently gained a lot of negative attention, with numerous articles highlighting their potential harm to health. They’re seemingly blamed for a wide range of health issues, from dementia to heart disease. In fact, the U.S. Food and Drug Administration is even contemplating measures to discourage the consumption of such foods.
If you enjoy hot dogs, these past few years might have felt pretty uneasy. But, despite what’s been said, there’s really no clear definition of what constitutes a UPF, nor is there solid evidence that the processing of food is inherently harmful.
The origin of the term “ultraprocessed food” dates back to a 2009 study from Brazil that introduced the Nova classification system to categorize the level of food processing. It aims to separate “food” from “ultraprocessed food products.” Yet, the term “ultra” itself remains ambiguous.
One major flaw is that the classification offers limited gradation of food processing. Foods are typically categorized as unprocessed, minimally processed, or ultraprocessed. Some scales even add “processed” as a middle category, but this creates a considerable gap. It essentially simplifies food into either good or bad categories. A more nuanced approach might involve terms like moderately processed or very heavily processed. Perhaps the term “ultra” should be reconsidered altogether, as it feels more sensational than scientific.
This limitation is significant since the Nova classification—the standard reference for most UPF research—doesn’t accurately account for the actual processing involved. Instead, it merely reflects researchers’ assumptions about what a UPF might look like. Many studies are based on discussions among a handful of researchers to establish definitions for UPFs.
In the original 2009 definition, any food that needed cooking—like bread or cured sausages—was deemed “ultraprocessed.” Yet, this notion seems quite off. Few would think of a fresh loaf of bread as ultraprocessed. Variations in how foods are grouped in research often stem from the personal views of the researchers involved.
For instance, corn chips can easily be made at home with basic ingredients, like corn flour and salt. I’ve actually made them before; they taste great. Many plain corn chips could be categorized as minimally processed because they require little effort to produce.
However, in reality, corn chips are typically classified as UPFs regardless of their actual processing level. The term “ultraprocessed” doesn’t necessarily reflect the extent of processing a food undergoes.
Take Professor Carlos Augusto Monteiro, the mind behind the Nova classification. In a 2017 study, he suggested that the real issue isn’t processing—as all foods are processed—but rather how these foods are “separated from nature.” Categories like UPFs are often marketed as branded and convenient. That phrasing feels a bit vague and subjective, doesn’t it?
The evidence base surrounding UPFs is also questionable. Much of the research indicating that UPFs negatively impact health tends to be poor quality and misleading. Many studies are observational, linking self-reported food consumption to health outcomes, but they don’t definitively show that UPFs cause health issues.
On top of that, robust randomized trials—which give participants either UPF-heavy diets or less processed ones—tend to show minimal negative consequences. At worst, a diet composed entirely of UPFs might lead to a slight weight gain compared to one without them, and even that is disputable.
This notion is debated, however. A recent publication argued that even those small negative effects in randomized trials could be attributed to differences in caloric density between the diets rather than processing itself. Typically, UPF diets consist of higher-calorie options, which may not be the case with less processed diets often featuring healthier alternatives. This disparity in food selection could easily skew the results.
Interestingly, the U.K. Food Standards Agency recently moved away from the UPF concept in their 2025 guidelines. They found that while many UPFs are unhealthy, others are not. Their recommendation is to focus on maintaining a healthy diet by limiting saturated fats, sugars, and salts while increasing vegetable and fiber intake. The core issue remains that the term UPF lacks a meaningful definition; it’s based more on subjective interpretation than any definitive processing criteria. Regulating food systems based on such vague ideas isn’t really ideal.
