Are ultra-processed foods a public health hazard?

Yes — the accumulating body of evidence strongly indicates that ultra-processed foods (UPFs) are a significant public health hazard, though with some important nuances and caveats.

The Evidence for Harm

Scale of the problem: The U.S. is among the biggest consumers of UPF in the world, with UPF making up more than half of what U.S. adults eat daily, and two-thirds of what kids and teens eat. Similarly, 57% of caloric intake in adults comes from ultraprocessed foods, and for children it's even higher, with 67% of children's daily calories from relatively empty ultraprocessed foods.

Broad disease associations: A major 2024 umbrella review in the BMJ examined 45 studies involving almost 10 million participants and found that eating more ultraprocessed foods is linked to a higher risk of dying from any cause and has ties to 32 health conditions, including heart disease, mental health disorders, type 2 diabetes, and other problems. That same analysis found "convincing" evidence that a diet high in ultra-processed foods increases the risk of death from cardiovascular disease by 50% and the risk of anxiety by 48%, and "highly suggestive" evidence that greater consumption increases the risk of death from heart disease by 66%, obesity by 55%, sleep disorders by 41%, Type 2 diabetes by 40%, early death from any cause by 21%, and depression by 20%.

Cardiovascular disease: Research for the NIH found that study participants with the highest UPF intake showed a 17% greater cardiovascular disease risk, 23% greater coronary heart disease risk, and 9% greater stroke risk compared with those with the lowest intake. A more recent meta-analysis found that each additional 100 g/day of ultra-processed food consumption was associated with a 14.5% higher risk of hypertension, 5.9% increased risk of cardiovascular events, 1.2% increased risk of cancer, 19.5% higher risk of digestive diseases and 2.6% higher risk of all-cause mortality.

Cancer: A large cohort study found younger women who eat more UPF, including highly processed bread, breakfast food and soda, may be more likely to develop colorectal cancer, in a study led by Harvard's T.H. Chan School of Public Health relying on data representing nearly 30,000 nurses. Earlier research in The BMJ found that men who ate the most ultra-processed foods had a 29% higher risk of developing colorectal cancer.

Mortality: A large multicentre study across nine European countries with 428,728 participants found that ultra-processed foods were positively associated with all-cause mortality, as well as mortality from circulatory diseases, cerebrovascular disease, ischemic heart disease, digestive diseases, and Parkinson's disease. Importantly, the same study found that "replacing processed and UPFs with unprocessed/minimally processed foods was associated with lower mortality risk."

Why this happens — causal evidence, not just correlation: A landmark NIH-funded randomized controlled trial provided rare experimental proof: when participants were on the ultra-processed food diet, they ate about 500 calories more every day compared to the non-ultra-processed diet, and gained an average of almost 1 kg after the week on the ultra-processed diet, losing that weight on the unprocessed diet.

Expert consensus: A 2025 Lancet series by over 40 health experts concluded that UPF are a leading contributor to chronic disease, with their widespread sale and consumption creating large corporate profits while making people sick. Nordic health authorities reviewing the evidence concluded that evidence regarding UPFs in relation to weight gain, CVD, type 2 diabetes, and all-cause mortality is considered strong enough to support dietary recommendations to limit their consumption.

Important Nuances

Not all UPFs are equal: Research co-author JoAnn Manson noted "not all UPFs are equal. Some UPFs appear to be worse for your heart than others," with the UPFs associated with the highest risk including sugar-sweetened beverages and processed meats such as hot dogs and deli meat, while those associated with the lowest risk included breakfast cereals, yogurt, and some whole grain products. Similarly, some ultra-processed foods, such as whole-grain breads and yogurts, are associated with reduced risks of chronic diseases, including colorectal cancer.

Mechanisms likely involve more than just nutrients: Ultra-processed foods contain significant amounts of added sugars, salts, and fats and can be hyper-palatable, meaning they are engineered to taste especially appealing, which may drive overconsumption independent of nutrient content alone.

Evidence base limitations: Most of this evidence comes from observational cohort studies rather than randomized trials. The NIH itself notes that while observational studies linking UPFs to cardiovascular disease are growing, rigorous clinical trials – the gold standard of scientific research – are largely lacking. There's also disagreement on classification: UPF classification systems like NOVA are used by WHO and other groups but not by the USDA, and there is debate among public policy experts, nutritionists, and researchers on how to categorize different types of processed foods. One Yale expert also cautioned that while the review findings weren't surprising, the incidence rates of the related health conditions are small — meaning relative risk increases don't always translate to large absolute risks for any individual.

Equity dimension: UPFs are frequently more affordable than less-processed foods or fresh produce, and their low cost and wide availability may drive health disparities among populations who already face hunger, undernutrition and higher rates of chronic disease — adding a social justice dimension to the public health concern.

Bottom Line

The weight of evidence — spanning dozens of large cohort studies, meta-analyses, an RCT demonstrating causal mechanisms, and consensus statements from major medical bodies — supports classifying heavy UPF consumption as a genuine public health hazard linked to obesity, diabetes, cardiovascular disease, certain cancers, mental health disorders, and premature death. However, the category is broad and heterogeneous, so the hazard is not uniform across all "ultra-processed" items, and researchers continue to debate classification systems and causal mechanisms.