Are ultra-processed foods a public health hazard?

Ultra-processed foods and public health — I'll pull the latest evidence to assess the hazard.

Yes - major international health authorities and a rapidly growing body of research now treat high consumption of ultra-processed foods (UPF) as a significant public health hazard, although the magnitude and mechanisms remain debated and not all UPFs appear equally harmful.

1. What are ultra-processed foods?

The most used framework is the NOVA classification, developed by Brazilian researchers in 2009.

> Ultra-processed foods (UPF) is a category of the nova classification that described a group of food that are typically industrially manufactured, generally derived from natural food or synthesized from other organic compounds.

The NOVA classification defines ultra-processed foods (UPFs) as “formulations of ingredients, mostly of exclusive industrial use, that result from a series of industrial processes.”

A more detailed NOVA definition describes them as:

> 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

Examples typically include soft drinks, packaged snacks, sweets, mass-produced breads, frozen pizza, instant noodles, flavored yogurt, fruit and milk drinks, diet products, baby food and most of what is considered junk food.

They are typically formulated to be convenient, shelf-stable, and hyperpalatable, often through the use of food additives such as preservatives, emulsifiers, colourings, and flavourings, using processes such as moulding, extrusion, hydrogenation, or frying.

The category does not evaluate nutritional content directly and is further distinguished by ingredients of no culinary use or additives with cosmetic functions such as flavours, colours, emulsifiers, sweeteners.

There is currently no commonly accepted definition by Codex Alimentarius and food regulators such as the European Food Safety Authority, and some authors have criticised the concept as poorly defined, and too focused on the type rather than the amount of food consumed.

2. Why they are considered a hazard: epidemiological evidence

Epidemiological data suggest that consumption of ultra-processed foods is associated with non-communicable diseases and obesity.

The strongest synthesis to date is a 2024 umbrella review in *The BMJ*:

> Need more reasons to stop eating ultra-processed food? How about 32 of them? That's the number of health problems noted in the largest-ever review of studies about the dangers of diets high in ultra-processed foods. The findings, published online Feb. 28, 2024, by The BMJ, come from a review of 45 analyses published in the last three years, involving about 10 million people in total.

Overall, direct associations were found between exposure to ultra-processed foods and 32 (71%) health parameters spanning mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic health outcomes.

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 with asthma, gastrointestinal disease, some cancers, and other issues were considered limited and need further investigation.

The review classified as convincing evidence (class I) direct associations between greater ultra-processed food exposure and higher risks of incident cardiovascular disease related mortality (risk ratio 1.50).

Other summaries note:

> There is strong scientific evidence that ultra-processed foods are linked to severe health risks, including cancer, cardiovascular and liver disease, and dementia.
> The evidence shows that these hyperpalatable foods ... are also linked to early death, or increased all-cause mortality.

A systematic review of 104 prospective studies for a 2025 Lancet series found that 92 demonstrated an association between an ultra-processed dietary pattern and increased risk of chronic disease in adults. The Lancet series concluded that greater dietary exposure to ultra-processed foods is associated with a higher risk of adverse health outcomes across the lifespan, with evidence for cardiometabolic and mental health effects rated convincing or highly suggestive.

Specific risk estimates reported in recent meta-analyses include:

A 2023 study published in The Lancet Regional Health — Europe similarly showed that a higher consumption was associated with an increased risk of cancer, along with cardiometabolic diseases.

3. How could they harm health?

Ultra-processed foods tend to be low in dietary fiber and high in calories, salt, added sugar and fat. They tend to promote overeating and weight gain, largely due to soft texture, high energy density and hyperpalatable nutrient combinations that alter satiety and food-reward.

According to the Lancet series, an increased uptake causes deterioration of diet quality, not just because UPFs are commonly high in fat, salt and sugar (HFSS), but also that they are hyperpalatable, low in health-protective phytochemicals.

Theorized mechanisms include higher density of calories, provoking overeating by combining fat and sugar, faster consumption because they are softer, or potentially containing harmful additives. One study noted that people who ate more ultra-processed foods had worse health outcomes even after accounting for nutritional quality, 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.

Other hypotheses include contaminants, certain food additives, high heat treatment, food addiction, and environmental pathways. The 2024 BMJ umbrella review noted the specific mechanism of the effects was not clear.

4. Scale of exposure

Sales have consistently increased or remained high since the 1990s.

As of 2023, the United States and the United Kingdom lead the consumption rankings, with 58% and 57% of daily calories, respectively. Consumption varies widely, from 25% to 35% in Chile, France, Mexico, and Spain, and 20% or less in Colombia, Italy, and Taiwan.

This makes high UPF diets a population-level exposure, not a niche behavior.

5. Nuance and debate: Not all UPFs are equally harmful

The publicizing of findings has sparked debate over categoric demonization, with some critics calling for a more balanced view.

Key points of criticism:

Some researchers argue existing evidence is limited to observational studies rather than randomized controlled trials, and that effects are largely accounted for by known factors such as nutrient composition.

There are also socioeconomic considerations: UPFs provide a large part of lower-income peoples' nutrition, and replacements may actually be less nutritious, while unnecessary anxiety and mistrust of science are social costs.

6. Public health response

Given claimed health and environmental impacts, there have been calls for better regulation and policy, including a 2023 BMJ paper stating “public health policies to reduce consumption cannot wait”.

The World Health Organization (WHO) is currently seeking experts to develop a guideline on consumption of ultra-processed foods to review currently available evidence and provide much-needed, evidence-based global guidance, as part of its mandate to promote healthier, safer, and more sustainable diets.

Consumption of such highly processed foods has been associated with a myriad of negative health effects in WHO's scoping documents.

National actions already include:

In the UK, the Scientific Advisory Committee on Nutrition (SACN) in 2022 reviewed literature and recommended further research, scheduling a review for June 2024, indicating regulators have so far considered evidence insufficient to use UPF terminology alone for guidelines.

A widely cited draft WHO target has been to limit ultra-processed foods to ≤10 % of total energy intake, though final global guidance is still under development.

7. Conclusion

In public health terms, most expert groups therefore frame high dietary patterns dominated by ultra-processed foods — rather than any single ultra-processed item — as a hazard, and recommend shifting toward minimally processed, whole foods, while calling for more precise classification and mechanistic research before blanket regulatory bans on all UPFs.

This information is for educational purposes and not medical advice. Discuss personal diet changes with a healthcare professional or registered dietitian.