Are ultra-processed foods a public health hazard?

Your question on ultra-processed foods is important — I'll gather the latest evidence on their health risks and what makes them a public health concern.

Yes, the overwhelming scientific consensus today is that high consumption of ultra-processed foods (UPFs) is a public health hazard - although debate continues about definitions, mechanisms and which UPFs are most harmful.

1. What are ultra-processed foods?

The term comes from the NOVA classification system developed by researchers at the University of Sao Paulo, Brazil in 2009-2010.

Nova was created by researchers at the University of Sao Paulo, Brazil in the format of a 2010 publication and Now, Nova recognizes four categories of food. The categories include unprocessed or minimally processed; processed culinary ingredients; processed foods; and UPFs.

UPFs are defined as:

> formulations made mostly or entirely from substances derived from foods and additives, with little if any intact unprocessed or minimally processed foods

More specifically, according to the NOVA classification, they are products that have undergone significant processing (chemical, physical, biological), which are generally formulated from industrial ingredients such as hydrogenated oils, protein isolates or glucose/fructose syrup, and "cosmetic" food additives such as colourings, artificial sweeteners, emulsifiers, flavour enhancers and other additives.

The framework defines UPFs as "ready-to-eat or heat-and-serve products that undergo extensive industrial processing … often containing multiple additives," such as candy and packaged snacks. These foods are "typically energy-dense and high in sugar and salt but low in dietary fiber, protein, vitamins and minerals".

Examples include soft drinks, packaged snacks, sweets, mass-produced bread, ready meals, reconstituted meat products, instant noodles and many breakfast cereals.

2. How widespread is consumption?

UPFs account for around 35% of calorie intake in France (and up to 60% in the United States).

Global UPF consumption has increased over the last several decades. In the US, UPFs made up 57% of energy consumption in 2018.

National surveys indicate the share of UPFs in diets is on the rise: estimated energy contribution tripled in Spain (11% to 32%) and China (4% to 10%) over the last three decades, and increased (10% to 23%) in Mexico and Brazil. Over the last three decades, UPF consumption increased in other countries. In Spain, UPF consumption increased from 11% to 31.7%.

A new three paper Series published in The Lancet, co-authored by ISER's Dr Paulo Serodio, reviews evidence that ultra-processed foods (UPFs) are displacing fresh and minimally processed foods and meals, worsening diet quality, and are associated with an increased risk of multiple chronic diseases.

The increase of UPFs in diets worldwide presents an urgent challenge to health that demands coordinated policies and advocacy action to address, says a new three-paper Series authored by 43 global experts and published in The Lancet.

3. Evidence linking UPFs to disease

Large-scale reviews

Higher ultra-processed food (UPF) intake is linked to a heightened risk of several major chronic health issues, such as digestive diseases, high blood pressure and metabolic syndrome/diabetes, as well as death, finds a pooled data analysis.

Every additional 100 g (3.5 ounces) consumed was associated with correspondingly greater risks.

The most comprehensive analysis to date:

A new meta-analysis of 51 prospective cohort studies involving more than 8 million people found that higher consumption of ultra-processed foods was associated with multiple chronic health risks, analyzing research from the Americas, Europe, Asia and Oceania, including studies published as recently as April 2026.

Results:

> Consumption of UPFs was associated with cardiovascular events (Hazard Ratio (HR) 1.24, 95% Confidence Interval (CI) 1.14 to 1.36), cancer (HR 1.12, 95% CI 1.04 to 1.21), obesity/overweight (HR 1.23, 95% CI 1.17 to 1.30), metabolic syndrome (MetS)/diabetes (HR 1.24, 95% CI 1.08 to 1.42)

Also digestive diseases (HR 1.31) and depression/anxiety (HR 1.27).

In that review:

> High consumption of ultra-processed foods was associated with higher risks of cardiovascular events (24%), cancer (12%), obesity/overweight (23%)
>
> each extra 3.5 ounces (100 grams) of ultra-processed food a day was linked to a higher risk of heart attacks and strokes, cancer, diabetes and death
>
> Obesity risk was 23% higher, cancer 12%, and death from any cause 18%.

Dose-response:

> The findings suggest that every additional 100 grams of UPFs consumed per day was associated with a 14% higher risk of cardiovascular events, 11% higher risk of high blood pressure

The Lancet Series systematic review encompassing 104 long-term studies, found 92 reported greater associated risks of one or more chronic diseases, with meta-analyses showing significant associations for 12 health conditions, including obesity, type 2 diabetes, cardiovascular disease, depression, and early death.

Earlier umbrella review found:

> Overall, direct associations were found between exposure to ultra-processed foods and 32 (71%) health parameters spanning mortality, cancer, and me

The Lancet Series consolidates a substantial evidence base linking UPF consumption to obesity, cardiovascular disease, cancer, mental ill-health, and premature mortality.

Evidence reviewed in the Series shows that diets high in UPFs are linked to overeating, poor nutritional quality (too much sugar and unhealthy fats, and too little fiber and protein) and higher exposure to harmful chemicals and additives.

Large prospective studies have linked higher consumption with increased risk of cardiovascular disease, hypertension, stroke, heart failure and diabetes, with adults with the highest UPF consumption having up to a 19% higher risk of heart disease, a 13% higher risk of atrial fibrillation.

The data examined in the first article in the series show that diets rich in ultra-processed foods are associated with overall overeating, poor nutritional quality and In addition, a systematic review covering 104 long-term studies, found that 92 of them reported a higher incidence of one or more chronic diseases associated with consumption.

4. Why might they be harmful? Proposed mechanisms

Mechanisms include poor nutrient profile, engineered hyper-palatability, altered food matrix, additives, rapid glycemic responses, and microbiome disruption.

Specifically:

> Mechanistic evidence increasingly points to the gut being highly susceptible to harm from UPF ingredients

5. Nuance and criticism

Scientists acknowledge limitations of the evidence:

Yes, there are valid criticisms of the NOVA classification system for UPFs, including heterogeneity within categories and the failure to distinguish beneficial processes such as fermentation.

While NOVA's framework groups together foods based on processing levels, critics point out that it does not determine a finished product's nutritional content.

> It is necessary to recognize that the NOVA Classification emphasizes the degree and purpose of food processing rather than nutritional composition

The Series authors acknowledge valid scientific critiques of Nova - such as lack of long-term clinical and community trials, an emerging understanding of mechanisms, and the existence of subgroups with different nutritional values - as key areas for future research. However, they argue future research must not delay immediate and decisive public health action.

Most evidence is observational (prospective cohorts), so cannot prove causation definitively; confounding by overall diet quality, lifestyle, and socioeconomic factors is possible. Some UPF subgroups (e.g., whole-grain packaged breads, unsweetened yoghurts classified as UPFs) may have different risk profiles. Randomized controlled trials are limited - one well-known inpatient trial found participants on an ultra-processed diet ate ~500 kcal/day more and gained weight vs. minimally processed diet - but longer trials are needed.

An expert quoted in the recent review cautioned that studies on UPF and health are based on "very unreliable data", highlighting that dietary assessment methods have error.

While a debate on ultra-processed foods within the scientific community is welcome in order to strengthen the level of available evidence, particularly on the mechanisms and factors involved, it should be distinguished from attempts by special interest groups to discredit current scientific evidence.

6. Public health response

Because of the strength and consistency of associations, The Lancet 2025 Series of 43 experts argues that although additional studies will be valuable, further research should not delay immediate action, declaring that evidence of UPFs harms justifies immediate public health action.

Proposed policies include:

Authors note global annual sales of $1.9 trillion, with UPFs the most profitable food sector, and argue corporate lobbying has delayed regulation, requiring a coordinated global public health response - Like coordinated efforts to challenge the tobacco industry.

Bottom line

Reducing UPFs - by cooking more from minimally processed foods, choosing water over sugary drinks, whole foods over packaged snacks/ready meals, and checking ingredients for long lists of additives - may help prevent disease and improve overall health, though total diet quality and lifestyle matter more than any single food.

This information is educational and not medical advice. Talk to your healthcare provider or dietitian about your personal diet.