Are ultra-processed foods a public health hazard?

Ultra-processed foods are linked to a growing list of chronic diseases — I'll pull the latest evidence on whether they amount to a public health hazard.

Are ultra-processed foods (UPFs) a public health hazard? The growing consensus among major medical reviews is: yes - they are increasingly described as an emerging public health challenge, but with important nuances.

1. What counts as ultra-processed?

The most widely used definition comes from the NOVA classification system:

> 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"

The Lancet Diabetes & Endocrinology describes them similarly as "formulations of ingredients, mostly of exclusive industrial use, that result from a series of industrial processes."

They are often high in sugar, salt, and fat; low in fibre, protein, and micronutrients; and containing additives, emulsifiers, stabilisers, colourants, and artificial sweeteners, generally having a poor nutrient profile. Examples include deli meat, microwaveable dinners, chips, sodas, packaged snacks, processed meats, sweetened cereals and soft drinks. They typically have long ingredients lists, with lots of additives such as preservatives, oil, sugar, salt, coloring, and flavoring.

Food processing itself is not automatically unhealthy, which is a major point in the current debate.

2. How widespread is exposure?

In the United States and United Kingdom, the most recent data show that 60 percent of the daily calories, on average, come from this kind of food.

More specifically:

•About 60 percent of Americans' total daily calories come from ultra-processed food

•In the United States today, UPFs make up nearly 60% of adults’ and 70% of children’s diets

•Ultra-processed foods now provide nearly 60% of the calories consumed by adults in the United States and about 70% of the energy intake of American children

•Hundreds of new ingredients now make up nearly 60% of the average adult's diet and almost 70% of children's diets in the United States

This displacement of minimally processed foods and freshly prepared meals by industrially formulated products is what public health researchers flag as the core concern.

3. What does the evidence show?

The largest review to date

A 2024 umbrella review in The BMJ pooled 45 meta-analyses covering nearly 10 million people. The review is frequently cited as the most comprehensive to date.

•Researchers included 45 distinct pooled analyses encompassing a total population of almost 10 million participants

•The analysis, which included 45 unique pooled analyses and 9,888,373 participants, found direct associations between 32 health parameters and exposure to ultra-processed food

•Overall, direct associations were found between exposure to [UPF] and 32 (71%) health parameters spanning mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic health outcomes

Harvard Health summarized the graded evidence:

> 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

Other syntheses report similar magnitudes:

•Convincing evidence showed that higher ultra-processed food intake was associated with around a 50% increased risk of cardiovascular disease-related death, a 48-53% higher risk of anxiety and common mental disorders, and a 12% greater risk of type 2 diabetes

•A meta-analysis of 23 observational studies found adolescents with higher consumption exhibit a striking 63% greater likelihood of being overweight or obese compared to their peers with lower UPF intake

The BMJ umbrella review was described as underscoring that higher exposure is associated with an increased risk of 32 damaging health outcomes including cancer, major heart and lung conditions, mental health disorders, and early death.

Researchers also note research has shown that diets high in ultra-processed foods are linked to more than 30 health conditions, and that convincing evidence supported direct associations between greater exposure and higher risks of incident cardiovascular disease-related mortality and type 2 diabetes, as well as anxiety and combined mental disorder outcomes.

The Lancet called the findings "yet another wake-up call," noting UPFs are strongly linked to poor health outcomes (increased risk of diet-related chronic diseases such as obesity, type 2 diabetes, cardiovascular disease, and certain cancers).

4. Why would they be hazardous? Proposed mechanisms

No single mechanism is proven, but researchers point to multiple pathways:

•The underlying mechanisms likely involve multiple pathways, including gut microbiota dysbiosis, toxic effects of food additives, overconsumption driven by ultra-high energy density, and nutrient displacement effects

•Engineered for taste and texture, they bypass natural satiety signals leading to overconsumption

•Additives and processing may disrupt the microbiome and promote inflammation

•Food scientists formulate these products to reach the "bliss point" — the precise combination of sugar, salt, and fat that maximizes palatability and encourages overconsumption

•Ultra-processed foods are typically "infused with artificial ..." and low in fiber, which starves beneficial gut microbes, while emulsifiers can disrupt the gut microbiome and weaken intestinal integrity

Other hypothesized contributors include chronic low-grade inflammation, elevated triglycerides from refined carbohydrates, rapid glycemic responses stressing pancreatic beta cells, and altered food structure making foods easier to overconsume and less satiating.

5. The nuance: Not all UPFs appear equally harmful

Major reviews and editorials stress caution about over-generalization:

•"While many ultra-processed foods tend to be of poor nutritional quality and should generally be limited or avoided, processing itself is not inherently harmful"

•"Is processed food automatically unhealthy? ... No. ... Processing itself isn't necessarily harmful"

•"Many people have been told to avoid processed foods, but the science is clearly telling us that we need to be more nuanced ... Processed meat like bacon, hot dogs, and deli meat should absolutely be avoided, but many plant-based foods that are considered ultra-processed, like breads, cereals, and meat alternatives are actually good for your health."

The category itself is extraordinarily broad, encompassing everything from sugary beverages and packaged snack foods to whole-grain breakfast cereals, fortified foods, plant-based meat alternatives, and infant formula.

Critics also note:

•The term could create confusion among consumers and policymakers, noting that ultra processed does not necessarily mean unhealthy

•Many nutritious, safe and essential foods – including milk, yogurt and cheese – undergo processing to ensure quality, safety and accessibility

•Some randomized controlled trials often cited were not designed to isolate 'ultraprocessing' from well-known nutritional factors like sugar, salt and fat.

Most evidence is observational, so causation is hard to prove, and confounding by overall diet quality, socioeconomic status, and lifestyle remains possible. The dose-response relationship matters: health risks start cropping up once you begin eating more than two servings a day, according to some researchers.

6. Public health interpretation

Because of the strength and consistency of associations, but also the nuance:

•Some institutions have framed UPF overconsumption as an emerging public health challenge for nutrition and functional health

•Others argue policies should target subcategories of harmful UPFs (especially sugary drinks, processed meats, salty snacks) rather than all NOVA Group 4 foods, and promote minimally processed diets to support cardiovascular health.

•The 2025-2030 Dietary Guidelines for Americans debate reflects this tension, avoiding the term "ultra-processed foods" precisely because an undefined or inconsistently applied term risks discouraging consumption of nutrient-rich foods that are vital to public health.

Bottom line: Based on the largest umbrella reviews to date, high consumption of ultra-processed foods is consistently associated with higher risks for all-cause mortality, cardiovascular mortality, type 2 diabetes, obesity, depression and anxiety, and other chronic conditions. That pattern, combined with the fact that these foods now dominate calories in many high-income countries, has led many researchers and public health bodies to treat high UPF diets as a public health hazard — while also calling for more nuanced definitions, better mechanistic research, and policies that distinguish the most harmful products from more nutritious industrially processed foods.

1.Ultra-processed foods: yet another wake-up call — https://www.thelancet.com/journals/landia/article/PIIS2213-8587(25)00139-1/fulltext

Citations (2)

1thelancet.comAcademic
Ultra-processed foods: yet another wake-up call
Backs: “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". The Lancet Diabetes & Endocrinology describes them…”
2harvard.eduAcademic
More evidence that ultra-processed foods harm health
Backs: “They are often high in sugar, salt, and fat; low in fibre, protein, and micronutrients; and containing additives, emulsifiers, stabilisers, colourants, and artificial sweeteners, generally having a poor nutrient profile. Examples include deli meat, microwaveable dinners, chips, sodas, packaged snacks, processed meats,…”