From packaged snack cakes to sugary breakfast cereal and reheat-and-eat meals, ultra-processed foods now make up an estimated majority of the calories in the typical diet in high-income countries, and can account for as much as 58 percent of total daily energy intake in some of them. A rapidly growing body of research is linking heavy consumption of these foods to a long list of health problems, including a higher risk of dying earlier than people who eat more minimally processed meals, and federal health researchers are now racing to understand exactly why.
Defining What Counts as Ultra-Processed
Ultra-processed foods are typically defined using the Nova classification system, which sorts foods by how much industrial processing and how many additive ingredients they contain rather than by nutrient content alone. Under that framework, ultra-processed products include items manufactured with ingredients rarely found in a home kitchen, such as hydrogenated oils, high-fructose corn syrup, emulsifiers, and artificial flavoring or coloring agents. Common examples include packaged snack cakes, sugar-sweetened sodas, chicken nuggets, heavily additive-laden flavored yogurts, and most reheat-and-eat frozen meals, distinguishing them from foods that are merely processed in a simpler way, such as canned vegetables or bagged salad. Consumption of these foods has risen rapidly not only in wealthier nations but increasingly in low- and middle-income countries as well, as packaged and branded foods spread through global supply chains.
Nearly Ten Million People, One Consistent Signal
A 2024 umbrella review pooled data from 45 separate meta-analyses covering close to 10 million people, testing for links between ultra-processed food consumption and 32 distinct health outcomes, according to a summary released by the journal’s publisher. The review’s strongest, most convincing evidence centered on cardiovascular disease: people with the highest ultra-processed food intake faced roughly a 50 percent greater risk of dying from heart-related causes, along with a 48 to 53 percent higher risk of anxiety and other common mental disorders and a 12 percent greater risk of type 2 diabetes. A second, slightly less certain tier of evidence linked heavy ultra-processed food consumption to a 21 percent greater risk of death from any cause, sharply higher risks, 40 to 66 percent, of dying from heart disease, developing obesity or type 2 diabetes, or experiencing sleep problems, and a 22 percent higher risk of depression. The review’s authors called for urgent public health measures, including clearer front-of-package labeling and limits on marketing to children, arguing the evidence base was now too consistent to treat as inconclusive.
What a Large Federal Cohort Found
Government-funded researchers have reached similar conclusions using different data. A large observational effort backed by the National Heart, Lung, and Blood Institute followed a United States cohort of more than 200,000 participants alongside a meta-analysis covering 1.2 million people, and found that the heaviest consumers of ultra-processed foods faced a 17 percent greater risk of cardiovascular disease, a 23 percent greater risk of coronary heart disease, and a 9 percent greater stroke risk compared with the lightest consumers. That research also found meaningful differences within the category: sugar-sweetened beverages and processed meats such as hot dogs and deli meat carried the highest risk, while some breakfast cereals, yogurts, and whole-grain products technically classified as ultra-processed showed comparatively little added risk, suggesting the category is not uniformly harmful from one food to the next.
The Clinical Trial That Showed Cause and Effect
Observational studies can show association but not proof of cause, which is why a 2019 randomized, controlled trial conducted at the National Institutes of Health Clinical Center carries particular weight. Twenty healthy adult volunteers spent a month living at the research facility, eating two weeks of meals built from ultra-processed ingredients and two weeks of meals built from minimally processed ingredients, with both diets matched exactly for calories, sugar, fat, salt, and fiber. Participants eating the ultra-processed diet consumed roughly 500 more calories per day than when eating the unprocessed diet, ate at a faster pace, and gained close to two pounds over two weeks, while losing an equivalent amount on the unprocessed diet, giving researchers rare direct evidence that the ultra-processed foods themselves, not just their nutrient content, drove the extra eating.
Open Questions About the Mechanism
Researchers still do not fully understand why ultra-processed foods drive people to eat more calories when the nutrient content is held constant, though several theories are under active investigation, including how quickly the foods are eaten, how they affect appetite-regulating hormones, and whether certain additives disrupt the gut microbiome or trigger low-grade inflammation. Federal researchers have also noted that ultra-processed food consumption is unevenly distributed, with lower-income populations tending to eat more of it, driven partly by cost and limited access to fresher alternatives, adding a public health dimension to a question that started out as a matter of individual diet.
This article was produced with the assistance of AI and reviewed by Morning Overview editors.
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