Are ultra-processed foods a public health hazard?

Ultra-processed foods are under intense scrutiny — I'll pull the latest evidence on their public-health impact.

Yes - a large and growing body of evidence links high consumption of ultra-processed foods (UPFs) to adverse health outcomes, and leading researchers and public health bodies now describe high UPF intake as a public health concern requiring population-level action, although debate remains about causality, heterogeneity within the UPF category, and the best policy response.

1. What are ultra-processed foods?

The most widely used definition is the NOVA classification system, developed in 2009 by Brazilian scientists and recognized by the World Health Organization.

NOVA classifies foods into four groups, with group 4 being ultra-processed:

> 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

They are generally formulated from industrial ingredients such as hydrogenated oils, protein isolates or glucose/fructose syrup, and "cosmetic" food additives (colourings, artificial sweeteners, emulsifiers, etc.) and are typically products with five or more ingredients listed on the label, engineered for convenience.

The food environment itself now works against healthy eating - the rise of UPFs is described as one of the most consequential public health developments of our time, with consumption increasing globally and dominating diets in high-income countries. Public health concern is not food processing as a broad technological practice, but the increasing displacement of minimally processed foods and freshly prepared meals by industrially formulated ultra-processed foods.

2. Epidemiological evidence of harm

Evidence of the harmful effects of ultra-processed foods is mounting.

Umbrella review in The BMJ (2024)

The most comprehensive synthesis to date is a 2024 umbrella review published in The BMJ (Lane et al. 2024):

> To evaluate the existing meta-analytic evidence of associations between exposure to ultra-processed foods, as defined by the Nova food classification system, and adverse health outcomes

It was a systematic umbrella review of existing meta-analyses that applied pre-specified evidence classification criteria graded as convincing (“class I”), highly suggestive (“class II”), suggestive, weak or no evidence, and assessed quality using GRADE.

Results:

•The search identified 45 unique pooled analyses, including 13 dose-response associations and 32 non-dose-response associations (n=9,888,373)

•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

Graded evidence:

•Convincing evidence (class I) supported direct associations between greater ultra-processed food exposure and higher risks of incident cardiovascular disease related mortality (risk ratio 1.50, 95% confidence interval 1.37 to 1.63) and type 2 diabetes (dose-response risk ratio 1.12, 1.11 to 1.13), as well as higher risks of prevalent anxiety outcomes (odds ratio 1.48, 1.37 to 1.59) and combined common mental disorder outcomes (odds ratio 1.53, 1.43 to 1.63)

•The review also found consistent evidence linking high consumption to increased risks of 32 serious health outcomes, including cardiovascular disease, mental health disorders, and premature death

Other reports of the same review note:

•Highly suggestive (class II) evidence indicated that greater exposure to ultra-processed foods was directly associated with higher risks of incident all cause mortality (risk ratio 1.21, 1.15 to 1.27), heart disease related mortality (hazard ratio 1.66, 1.51 to 1.84), type 2 diabetes (odds ratio 1.40, 1.23 to 1.59), and depressive outcomes (hazard ratio 1.22, 1.16 to 1.28)

•together with higher risks of prevalent adverse sleep related outcomes (odds ratio 1.41)

•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

The authors concluded:

> Greater exposure to ultra-processed food was associated with a higher risk of adverse health outcomes, especially cardiometabolic, common mental disorder, and mortality outcomes
> These findings provide a rationale to develop and evaluate the effectiveness of using population based and public health measures to target and reduce dietary exposure to ultra-processed foods for improved human health

A subsequent systematic review of 104 prospective studies found that 92 demonstrated an association between an ultra-processed dietary pattern and increased risk of chronic disease in adults.

Large 2026 systematic review (51 cohort studies, 8.8 million adults)

A 2026 analysis in Family Medicine and Community Health by Liu et al. analyzed the effects of UPFs in 51 prospective cohort studies, composed of 8,819,894 adults aged 23.9 to 77 years.

It found higher UPF intake raised the risk for:

•overweight and obesity by 23% (HR = 1.23)

•cardiovascular events like stroke, coronary artery disease, transient ischemic attack and heart attack by 24% (HR = 1.24)

•metabolic syndrome and diabetes by 24% (HR = 1.24)

•cancer by 12% (HR = 1.12)

•digestive diseases by 31% (HR = 1.31) and

•all-cause death by 18% (HR = 1.18)

Summary figures from related reporting:

•The group that ate the most ultra-processed foods had a 24% higher risk of cardiovascular events than the group that ate the least. Cancer risk was 12% higher, obesity and overweight risk 23% higher, and metabolic syndrome and diabetes risk 24% higher. Depression and anxiety were 27% higher, digestive disorders 31% higher, and all-cause mortality risk 18% higher

Dose-response:

•Each additional 100 g daily intake of UPFs raised the risk for all-cause death by 3% (HR = 1.03); cancer by 4% (HR = 1.04); hypertension by 11% (HR = 1.11) cardiovascular events by 14% (HR = 1.14); and metabolic syndrome and diabetes by 2% (HR = 1.02)

•The analysis found a dose-response relationship, in which disease risk rose along with consumption

•Every 10% increase in weight and energy intake was also tied to a 16% higher risk for metabolic syndrome and diabetes

Other supportive data: Eating more ultra processed food may increase lung cancer risk by 41%, and research in The BMJ offered fresh evidence that eating more than four daily servings linked to a 62% higher risk of premature death.

High consumption of ultra-processed foods has been consistently associated with increased risks of obesity, cardiovascular disease, type 2 diabetes, and all-cause mortality.

3. Potential mechanisms

Researchers propose several pathways:

> Emerging evidence suggests that the combination of multiple additives, such as artificial sweeteners, may have a potential ‘cocktail effect’
> Laboratory research showed that the extensively altered physical composition of UPFs may have implications for cardiometabolic health by affecting key biological pathways such as gut microbiota composition, host-microbiota interactions, inflammation, oxidative stress and insulin resistance

Recent NutriNet-Santé studies ( >100,000 participants) found food colouring additives as a whole were associated with a 38% increase in risk of type 2 diabetes among higher consumers and a 14% increase in overall cancer risk, while preservatives as a whole were associated with a 24% increase in hypertension risk. These additives are characteristic markers of ultra-processed foods. The authors conclude these findings underscore the need for health authorities to reassess the safety of these additives.

Clinical trials show people who consume a diet high in ultra-processed foods tend to overeat and gain unwanted weight, with one small controlled trial finding adults ate about 508 more calories a day and gained roughly 0.9kg on a matched ultra-processed diet.

4. Public health implications

Authors and commentators argue the evidence is now strong enough that doctors should begin routinely discussing ultra processed food consumption with patients as part of normal healthcare, and highlight the need for integrated, risk factor-oriented management in primary care.

Specific advice emerging:

> Primary care practitioners may advise gradual reduction of UPFs intake towards approximately 10%-20% of total daily energy intake, while considering which UPF subtypes are most strongly associated with adverse outcomes
> Replacing UPFs with minimally processed alternatives, rather than restriction alone, may provide a more sustainable and patient-centered approach

The BMJ umbrella review authors explicitly call for population based and public health measures to target and reduce dietary exposure.

5. Nuances, limitations and debate

Despite strong associations, experts urge caution:

•Observational nature: studies are primarily observational, so causality cannot be inferred, and confounding factors may play a role. Large cohort studies link higher UPF intake to several health outcomes; they cannot, on their own, establish that UPFs caused those outcomes.

•Quality of evidence: Overall, using the GRADE framework, 22 pooled analyses were rated as low quality, with 19 rated as very low quality and four rated as moderate quality. Associations for asthma, gastrointestinal disease, some cancers were limited and need further investigation.

•Not all UPFs are equal: Not all UPFs are equal. Intake of certain ultra processed foods – such as artificially and sugar sweetened drinks, animal-based products, and ready-to-eat mixed dishes – were associated with higher risk while other ultra processed foods – cereals, dark and whole grain breads, packaged snacks, fruit based products, and yogurt or dairy based desserts – were associated with lower risk. Different UPFs, different outcomes: Not all ultra-processed foods carry the same health risks—some, like cereals and breads, may even offer protective benefits.

•Correlation vs causation: What we do know is that diets high in UPFs tend to be higher in calories, lower in ... But correlation doesn't equal causation. People who eat more UPFs also tend to have other lifestyle factors that influence their health - lower income, less access to fresh foods, higher stress levels. Results may also be subject to reverse causality.

•Classification debate: The NOVA classification does not consider a food’s nutritional value — ultra-processed foods can be healthy and minimally processed ones unhealthy, leading some to question advising people to universally ‘avoid ultra-processed foods’. The World Health Organization’s FAO noted that practically all food is processed somehow, calling for evidential reasoning. Diet quality outweighs food processing for disease risk in some analyses.

In short: while the weight of epidemiological meta-analyses consistently associates higher UPF exposure with cardiometabolic mortality, diabetes, mental health disorders, obesity, cancer and all-cause mortality, the evidence is currently graded as low to very low certainty for most outcomes and remains observational, with heterogeneity within the UPF category.

Bottom line: Based on 2024-2026 umbrella and systematic reviews covering nearly 10 million people, higher UPF intake is associated with a broad range of adverse health outcomes and is increasingly treated as a modifiable public health hazard warranting dietary guidance and policy attention, while research continues to clarify which subtypes and mechanisms drive risk and how best to define and regulate UPFs.

Citations (3)

1fabresearch.orgNot yet classified
FAB: Lane M et al 2024 - Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses
Backs: “Umbrella review in The BMJ (2024). The most comprehensive synthesis to date is a 2024 umbrella review published in The BMJ (Lane et al. 2024): To evaluate the existing meta-analytic evidence of associations between exposure to ultra-processed foods, as defined by the Nova food classification system, and adverse health…”
2healio.comNot yet classified
More data tie ultra-processed foods to chronic disease, death
Backs: “Large 2026 systematic review (51 cohort studies, 8.8 million adults). A 2026 analysis in Family Medicine and Community Health by Liu et al. analyzed the effects of UPFs in 51 prospective cohort studies, composed of 8,819,894 adults aged 23.9 to 77 years.”
3inserm.frNot yet classified
Archives des Public health - Inserm Newsroom
Backs: “Laboratory research showed that the extensively altered physical composition of UPFs may have implications for cardiometabolic health by affecting key biological pathways such as gut microbiota composition, host-microbiota interactions, inflammation, oxidative stress and insulin resistance. Recent NutriNet-Santé…”