Are ultra-processed foods a public health hazard?

Ultra-processed foods (UPFs) have become one of the most contested topics in nutrition science, and current evidence increasingly supports the view that they pose a genuine public health concern—though the picture is nuanced.## Yes—the weight of current evidence indicates ultra-processed foods (UPFs) are a genuine public health hazard, though the science is still refining the "why" and "how much."

What counts as a UPF?

Most research relies on the NOVA classification, which sorts foods by degree and purpose of processing rather than nutrient content. NOVA categorizes foods into four groups based on the extent and purpose of processing: group 1 non-processed or minimally processed items like fresh fruits and vegetables, group 2 processed cooking ingredients like oil, flour, and sugar, group 3 processed items like some canned foods, and group 4 UPFs like packaged chips, cookies, and pre-made meals. UPFs are generally industrially manufactured, generally derived from natural food or synthesized from other organic compounds, and typically formulated to be convenient, shelf-stable, and hyperpalatable, often through food additives such as preservatives, emulsifiers, colourings, and flavourings.

The evidence linking UPFs to disease is substantial and growing

A major 2024 umbrella review found strong associations across dozens of outcomes: a 2024 review of 45 metanalyses, covering nearly 10 million study participants, 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%. It also found "highly suggestive" evidence that greater consumption of these foods increases the risk of death from heart disease by 66%, the risk of obesity by 55%, sleep disorders by 41%, Type 2 diabetes by 40%, early death from any cause by 21% and depression by 20%.

A 2025 review synthesized findings covering 32 distinct health conditions, concluding 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.

More specific findings from recent large studies include:

Moving beyond correlation: causal mechanisms are emerging

Critics have long argued UPF studies are merely observational and confounded by broader unhealthy lifestyles. But 2025 brought experimental evidence. A randomized controlled trial found harmful effects of UPFs on weight gain and metabolic and reproductive health, regardless of excessive caloric intake. Researchers suspect several mechanisms beyond basic nutrition, including food additives. Notably, an animal study found two widely consumed food additive emulsifiers caused transgenerational microbiota alteration that led to increased long-term susceptibility to metabolic and inflammatory diseases. This matters because safety assessments of food additives have so far been performed substance by substance, while mixtures of additives are consumed daily by billions of people worldwide.

A landmark three-paper Lancet series in 2025 reinforced this, concluding that ultra-processed foods are rapidly replacing fresh and minimally processed meals around the world, with evidence linking rising UPF intake to poorer diet quality and higher risks of multiple chronic diseases. The proposed mechanisms include gross nutrient imbalances; overeating driven by high energy density, hyper-palatability, soft texture, and disrupted food matrices; reduced intake of health-protective phytochemicals; and increased intake of toxic compounds, endocrine disruptors, and potentially harmful classes and mixtures of food additives.

Scale of the problem

This isn't a marginal dietary issue—UPFs dominate modern diets. Recent CDC data show 53% of the calories adults consumed daily, on average, came from ultraprocessed foods between 2021 and 2023, and for children 18 and younger, the figure is 61.9%. Globally, the market has expanded dramatically: global UPF sales grew from $1.5 trillion in 2009 to $1.9 trillion in 2023.

Important caveats and scientific debate

The picture isn't unanimous. Critics argue NOVA is a blunt instrument. One key critique: the common criticisms of ultra-processed foods do not apply to soya-based meat and dairy alternatives more so than they do to their animal-based counterparts, despite the former being classified as UPF—simply put, soya burgers are not Twinkies, even though NOVA similarly classifies these products. Other researchers note that processed foods have positive nutrient benefits beyond those of the raw or home-prepared product, and that this is not only misleading but also untrue that all processed foods are nutrient-poor. There's also active work to refine classification, since current classification systems, including the dominant NOVA system, are typically not suitable for identifying which factors of these foods may be harmful.

Bottom line

Despite legitimate debates about classification precision, the convergence of large epidemiological cohorts, systematic reviews/meta-analyses, and now experimental/mechanistic evidence has shifted scientific consensus toward viewing high UPF consumption as a genuine driver of chronic disease risk—not just a marker of an already-unhealthy lifestyle. Public health bodies and journals like The Lancet are increasingly treating this as a policy priority, with experts calling for bold, coordinated policy action to counter corporate influence and shift food systems toward healthier options. That said, occasional consumption isn't the concern—it's the fact that UPFs have become the dominant source of calories in many populations, particularly among children.