Are ultra-processed foods a public health hazard?

Ultra-processed foods and public health — I'll pull the latest evidence on risks and what health agencies are saying.

Yes - major health agencies and large reviews of epidemiological evidence increasingly treat diets high in ultra-processed foods (UPFs) as a public health hazard, although there is nuance about heterogeneity within the category.

What are Ultra-Processed Foods?

The term originates from the NOVA food classification system, which defines foods in four categories ranging from least to most processed .

They encompass a broad range of ready to eat products, including packaged snacks, carbonated soft drinks, instant noodles, and ready-made meals. These products are characterised as industrial formulations primarily composed of chemically modified substances extracted from foods, along with additives to enhance taste, texture, appearance, and durability, with minimal to no inclusion of whole foods.

Other definitions note they have one or more ingredients that wouldn't be found in a kitchen, like chemical-based preservatives, emulsifiers like hydrogenated oils, sweeteners like high fructose corn syrup, and artificial colors and flavors and undergo processing techniques like pre-frying, molding, extrusion, fractioning.

How Widespread Is Exposure?

In the United States the exposure is very high:

Analyses of worldwide ultra-processed food sales data and consumption patterns indicate a shift towards an increasingly ultra-processed global diet. Across high income countries, the share of dietary energy derived from ultra-processed foods ranges from 42% and 58% in Australia and the United States, respectively.

What Does the Evidence Show?

The most comprehensive assessment to date is an umbrella review published in The BMJ on Feb 28, 2024:

Graded evidence from that review:

Other syntheses support this:

U.S. federal agencies have called the threats clear and convincing: “The threats posed to our health by foods often considered ultra-processed are clear and convincing"

Why Are They Considered Hazardous? Plausible Mechanisms

Researchers point to multiple overlapping features, not just nutrients alone:

These may act through known or plausible physiological mechanisms including changes to the gut microbiome and increased inflammation

A Tufts study noted people who ate more ultra-processed foods had worse health outcomes, even after accounting for the overall nutritional quality of the foods, suggesting factors beyond nutrients—such as changes to foods’ cellular structure, loss of beneficial chemical compounds, additives, and chemicals from packaging—may create health risks

Are All Ultra-Processed Foods Equally Hazardous?

No. This is an area of active debate and a key caveat.

The most harmful sub-categories consistently identified are sugary drinks and processed meats, and salty snacks, refined snack foods, instant noodles, candy, and sugar-sweetened beverages.

Limitations and Public Health Interpretation

The BMJ authors and others emphasize limitations:

Despite low-to-moderate certainty for many individual outcomes, the consistency, dose-response relationships, and breadth of associated conditions have led authors to conclude:

Proposed public health actions discussed include front-of-package labels, soda taxes, reformulation incentives, school meal standards, and improving affordability and access to minimally processed foods, as UPFs remain shelf stable, convenient, and cheaper per calorie.

Bottom line: Diets high in ultra-processed foods, particularly those high in sugary drinks, processed meats, and calorie-dense salty/sweet snacks, are consistently linked in large population studies to higher risks of cardiometabolic disease, mental health disorders, and early death, and are widely considered a public health hazard. The degree of risk depends on which UPFs, how much is consumed, and what they replace in the diet; some fortified, fiber-rich or protein-rich UPFs can fit into a healthy pattern, but the overall pattern of high UPF consumption — which now provides over half of calories in the U.S. — is considered detrimental to population health.