Ultra-processed food has become one of the defining villains of modern nutrition. It is blamed for everything from expanding waistlines to a growing burden of chronic disease, appears routinely in scientific papers and dietary discussions, and has become shorthand for much of what seems wrong with the modern food supply. Yet ask a surprisingly simple question — What, exactly, makes a food ultra-processed? — and the answer becomes complicated very quickly.
The United States does not currently have a single authoritative definition for the term. The Food and Drug Administration and Department of Agriculture are now working to create one, an undertaking that could eventually influence dietary guidance, food labeling, government programs and perhaps even how some of the most familiar products in the supermarket are regulated.
The timing is significant. The FDA says foods commonly considered ultra-processed account for an estimated 70 percent of the U.S. food supply, while more than 60 percent of the calories consumed by children come from these products. Research has repeatedly associated diets high in UPFs with obesity, cardiovascular disease and other adverse health outcomes. But “processed” and “ultra-processed” are not interchangeable, and that distinction is where much of the confusion begins.
Nearly everything we eat has been processed in some way. Milk is pasteurized. Vegetables are frozen. Coffee beans are roasted. Olive oil is extracted from olives, yogurt is fermented and canned tomatoes have been cooked and preserved. Processing itself does not make a food nutritionally undesirable. The concept of ultra-processing tries to describe something different.
The most widely used system in scientific research is NOVA, developed by researchers at the University of São Paulo. Rather than classifying food primarily by calories, fat, carbohydrates or individual nutrients, NOVA divides it into four categories according to the nature, extent and purpose of processing. At one end are foods that are unprocessed or minimally processed: vegetables, fruits, eggs, meat, milk, rice and similar foods. There are also culinary ingredients such as butter, oils, sugar and salt, followed by traditional processed foods such as cheeses, canned vegetables and relatively simple breads.
The fourth category is where things become more controversial. NOVA describes ultra-processed foods broadly as industrial formulations made with substances derived from foods, chemically modified ingredients and additives often used to create flavor, texture, appearance or convenience. Soft drinks, many packaged snacks, reconstituted meat products, instant meals and numerous mass-produced baked goods can fall into this category.
The distinction can produce combinations that seem counterintuitive. A food can be high in calories, fat or salt without necessarily being ultra-processed, while another product with an impressive Nutrition Facts panel may qualify because of the way it was formulated and the ingredients used to produce it. That is part of what makes a federal definition so difficult.
The government must decide whether ultra-processing should be determined by the number or type of ingredients, particular additives, manufacturing techniques, changes to the original structure of a food, its nutritional composition — or some combination of those characteristics. The FDA and USDA formally asked scientists, industry and the public for input on precisely those questions in 2025. The agencies say a uniform definition is necessary before federal programs and policies addressing UPFs can be developed consistently.
There is good reason for the interest. In one of the most important experiments in this field, researchers at the National Institutes of Health brought 20 adults into a clinical research center and randomly assigned them to diets composed primarily of ultra-processed or minimally processed foods. The meals were designed to be comparable in calories and major nutrients, and participants were allowed to eat as much as they wanted.
On the ultra-processed diet, they consumed roughly 500 additional calories per day and gained about two pounds over two weeks. On the minimally processed diet, they lost approximately the same amount.
The experiment provided unusually strong evidence that something about the ultra-processed diet encouraged greater food intake. What it did not establish was precisely what that something was.
That question remains central to the scientific debate. Is the problem the processing itself? Energy density? Texture and eating speed? Particular combinations of fat and carbohydrates? Additives? Hyper-palatable formulations? Or simply that many foods classified as ultra-processed are convenient, inexpensive and easy to consume rapidly?
The answer matters enormously because the UPF category is remarkably broad. Treating every food that meets a technical definition as nutritionally equivalent could replace one kind of oversimplification with another.
That is why creating an official definition is more consequential than settling a matter of vocabulary. Once the federal government defines ultra-processed food, the term can potentially become a tool for policy. It could influence dietary recommendations, research, school and government food programs and, eventually, what consumers see on packages.
For decades, American nutrition policy largely evaluated food through its nutrients: calories, saturated fat, sodium, sugar, fiber, vitamins and minerals. The debate over ultra-processed foods introduces a different possibility — that how a food is manufactured may matter alongside what its Nutrition Facts panel says it contains.
The FDA and USDA have not yet decided exactly where that line should be drawn. But before Americans can be told with any precision to eat fewer ultra-processed foods, someone has to decide which foods those actually are. And that may prove much harder than it sounds.
Official sources: FDA: Ultra-Processed Foods · FDA, HHS and USDA initiative to define ultra-processed foods · NIH controlled trial of ultra-processed foods
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