Are ultra-processed foods a public health hazard?

Ultra-processed foods under the microscope — I'll gather the latest evidence on whether they pose a public-health risk.

Yes - the current scientific consensus is that high consumption of ultra-processed foods (UPFs) is a public health hazard, although debate continues about degree, mechanisms and whether all UPFs are equally hazardous.

1. What are ultra-processed foods?

There is no legal definition in U.S. statute or regulation, but researchers commonly use the NOVA classification introduced by Brazilian researchers in 2010.

Under NOVA, Ultra-Processed Foods (UPF; NOVA "Group 4") refers to "industrial formulations made entirely or mostly from substances extracted from foods (oils, fats, sugar, starch, and proteins), derived from food constituents (hydrogenated fats and modified starch), or synthesized in laboratories

Manufacturing techniques include extrusion, molding and preprocessing by frying

Products considered UPF are heterogeneous ranging from carbonated soft drinks to ready-to-eat food products, including:

Using NOVA definitions, some research estimates that 50%-70% of total U.S. dietary energy is derived from UPF

2. Evidence linking UPF to adverse health outcomes

The largest synthesis to date is a 2024 umbrella review in The BMJ.

> Hundreds of epidemiological studies and meta-analyses have reported associations between ultra-processed food consumption and adverse health outcomes. In a linked paper (doi:10.1136/bmj-2023-077310), Lane and colleagues have now carefully reviewed the evidence from 45 meta-analyses encompassing almost 10 million participants.1 They found direct associations between exposure to ultra-processed foods and 32 health parameters including mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic ill health

Other summaries report:

When scientists graded the evidence, they found the most convincing or highly suggestive evidence linked diets rich in ultra-processed foods with increased risks for premature death, cardiovascular disease, mental health disorders, diabetes, obesity, and sleep problems. Associations between ultra-processed foods and asthma, gastrointestinal disease, some cancers, and other health issues were limited and need further investigation.

Based on convincing evidence (class I), higher exposure to ultra-processed foods had direct associations with increased risks of incident CVD-related death (risk ratio [RR], 1.50, 95% confidence interval [CI], 1.37‒1.63) and type 2 diabetes. A pooled analysis of seven cohorts showed a 10% increase in ultra-processed food consumption to be associated with a 12% higher incidence of type 2 diabetes.

A second large synthesis reinforces this:

Harvard Health summarized: the most convincing evidence linked diets rich in UPF with increased risks for premature death, cardiovascular disease, mental health disorders, diabetes, obesity and sleep problems, while other associations need further study.

Clinical experimental evidence also exists: Researchers have also conducted clinical trials showing that people who consume a diet high in ultra-processed foods tend to overeat and gain unwanted weight.

Although large observational studies do not prove cause and effect, the research does suggest an association between ultra-processed diets and heart disease.

The Congressional Research Service notes:

> Some research links UPF consumption with adverse health outcomes; however, the evidence remains mixed across various populations, health outcomes, and types of UPF consumed

There remains an ongoing debate regarding how or why UPF may be linked to health problems, including the extent to which the level of food processing, as compared with other factors like nutritional content, may or may not link to health risks

3. Why would UPF be hazardous? Proposed mechanisms

Researchers propose multiple pathways operating simultaneously:

> “Ultra-processed foods affect the body through multiple pathways simultaneously — excess sugar, salt, and calories; food additives; loss of nutrients during processing; and contaminants introduced by packaging — so it makes sense that the health consequences would show up across many organ systems rather than just one.”

4. Nuance: Not all UPFs are equally harmful

Major reviews stress heterogeneity:

The American Heart Association, industry groups, and some nutrition scientists argue NOVA “arbitrarily classifies foods based on perception” and penalizes fortified cereals, whole-grain breads and yogurts that may provide important nutrients, while others argue the system helps consumers identify additives and make healthier choices.

5. Public health interpretation

Because of the breadth of associations — 32 of 45 outcomes (71%) in the BMJ umbrella review, the BMJ editorial concluded:

> “Overall, the authors found that diets high in ultra-processed food may be harmful to most—perhaps all—body systems.”

Findings have been described as underscoring need for urgent research to understand how ultra-processed foods affect health and measures to target and reduce exposure.

Health authorities including WHO have flagged UPF as a growing threat, and the U.S. Dietary Guidelines Advisory Committee is now specifically examining: “What is the relationship between consumption of dietary patterns with varying amounts of ultra-processed foods and growth, body composition, and risk of obesity?” for the 2025-2030 Dietary Guidelines.

Policy options under discussion in Congress and at FDA include reassessment of GRAS additives, front-of-package nutrition labeling, limits on sodium/sugar, and better definition of processing levels, while balancing concerns about reformulation costs, food accessibility and avoiding stigmatizing nutrient-dense fortified foods.

Bottom line: Current epidemiology, graded as convincing to highly suggestive for cardiovascular mortality, type 2 diabetes, obesity, common mental disorders and all-cause mortality, strongly supports classifying habitual high UPF consumption — particularly sugar-sweetened beverages, processed meats, salty snacks and sweets — as a public health hazard. Evidence is less definitive for some cancers, asthma and gastrointestinal outcomes, and does not prove that every NOVA Group 4 food is inherently unhealthy in moderation.