Are ultra-processed foods a public health hazard?

I'll gather the latest evidence on whether ultra-processed foods pose a public health risk.

Yes, the majority of recent scientific evidence and expert bodies now characterize high consumption of ultra-processed foods (UPFs) as a major public health hazard, although debate continues about definition, mechanisms and whether all UPFs are equally harmful.

1. What are ultra-processed foods?

Under the widely used NOVA classification, there are four groupings of foods, with Group 4 being ultra-processed foods such as cakes, cookies, energy drinks, chips, and sweetened juices .

They are defined as:

> "industrial formulations with five or more ingredients" that contain substances that aren't typically used in culinary preparations

or

> ingredients "never or rarely used in kitchens, or classes of additives whose function is to make the final product palatable or more appealing"

Ultra-processed foods, including packaged baked goods and snacks, fizzy drinks, sugary cereals, and ready-to-eat or heat products, undergo multiple industrial processes and often contain colours, emulsifiers, flavours, and other additives. These products also tend to be high in added sugar, fat, and/or salt, but are low in vitamins and fibre.

There is no standard definition of what constitutes an ultra-processed food, though they are generally energy rich foods with little nutritional value, containing added fats, sugars and chemicals to preserve their shelf life and make them very palatable.

2. Scale of exposure - why it is a population-level issue

UPFs can account for up to 58% of total daily energy intake in some high income countries, and have rapidly increased in many low and middle income nations.

Analyses of worldwide ultra-processed food sales data and consumption patterns indicate a shift towards an increasingly ultra-processed global diet, although considerable diversity exists within and between countries and regions. Across high income countries, the share of dietary energy derived from ultra-processed foods ranges from 42% and 58% in Australia and the United States, respectively, to as low as 10% and 25% in Italy and South Korea.

Consumption statistics underscore the scale of the problem: in the UK and USA, more than 50% of the average diet comes from ultra-processed foods, while some populations, particularly younger, lower-income, or disadvantaged groups, consume up to 80% of their diet from these products.

In the US specifically:

The mean percentage of total calories consumed from ultra-processed foods (UPFs) eaten by everyone age 1 and older was 55%, during August 2021 and 2023, when the National Center for Health Statistics conducted its survey. The survey underscored a persistent difference by age; among those between the ages of 1 and 18, the mean consumption of UPFs was higher, 61.9% of calories.

The second paper showed that the consumption of UPFs is increasing around the world—and already represents more than half of all calories eaten in the United States, Australia and the UK.

3. Evidence linking UPFs to health harms

Epidemiological evidence is now considered consistent

The epidemiological evidence is now very consistent. Large prospective studies conducted around the world have linked higher consumption of ultra-processed foods with increased risk of cardiovascular disease, hypertension, stroke, heart failure and diabetes.

Umbrella review of almost 10 million people - 32 outcomes

The largest synthesis to date was an umbrella review of 45 distinct pooled meta-analyses from 14 review articles involving almost 10 million participants published in The BMJ on 28 Feb 2024. None were funded by companies involved in the production of ultra-processed foods.

> 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

> Consistent evidence shows that higher exposure to ultra-processed foods 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 graded evidence as convincing, highly suggestive, suggestive, weak, or no evidence:

> 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

> Highly suggestive evidence also indicated that higher ultra-processed food intake was associated with a 21% greater risk of death from any cause, a 40-66% increased risk of heart disease related death, obesity, type 2 diabetes, and sleep problems, and a 22% increased risk of depression

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, the authors say, and need further investigation.

Other meta-analyses found similar dose-response relationships:

> An international research team ... pooled data on 8,819,894 adults from 51 prospective cohort studies

Eating a lot of ultra processed foods was associated with higher risks of cardiovascular events (24%), cancer (12%), obesity/overweight (23%), metabolic syndrome/diabetes (24%), depression/anxiety (27%), digestive diseases (31%), high blood pressure (11%) and death from any cause (18%).

A 2024 review noted each 10% increment in UPF share and each additional 100g/day increment significantly raised risks for cardiovascular events, cancer and mortality, though authors note eight studies involving 118,946 participants were part of one subgroup analysis.

Clinical trial evidence

A 2019 clinical study conducted by former National Institutes of Health researcher Kevin Hall, for example, found this food category causes overeating and weight gain.

People who consume a diet high in ultra-processed foods tend to overeat and gain unwanted weight, according to randomized trials.

This "bliss point" engineering ... fosters compulsive overeating, with studies showing UPFs are consumed 500 calories more per day on average than unprocessed foods.

4. Proposed mechanisms

The precise mechanism for how UPFs cause such a wide range of health problems also remains unclear.

The researchers laid out numerous theories, including that UPFs contain a higher density of calories than fresh food, provoke overeating by combining elements such as fat and sugar, can be consumed more quickly because they are softer, or potentially contain harmful additives.

Other factors cited include:

Researchers have argued industry practices that foster a food environment dominated by unhealthy, energy-dense, highly processed foods are likely the biggest external contributor to addictive-like overeating and obesity.

5. Why public health bodies call it a hazard

Researchers warned Wednesday that rising global consumption of ultra-processed foods (UPFs) poses a major threat to health, calling for countries to subject some products made by huge food companies to marketing restrictions and taxes.

In a Lancet series in 2025, authors called for nations to introduce warnings on package labels, restrict marketing—particularly advertisements aimed at children—and tax certain UPFs, using the money to make fresh food more affordable for low-income households.

A BMJ editorial linked to the umbrella review argued:

> They point out that reformulation does not eliminate harm, and profitability discourages manufacturers from switching to make nutritious foods, so public policies and action on ultra-processed foods are essential

These include front-of-pack labels, restricting advertising and prohibiting sales in or near schools and hospitals, and fiscal and other measures that make unprocessed or minimally processed foods and freshly prepared meals as accessible and available as, and cheaper than, ultra-processed foods.

> It is now time for United Nations agencies, with member states, to develop and implement a framework convention on ultra-processed foods similar to the framework on tobacco

The WHO's International Agency for Research on Cancer has already formally categorized processed meats - a subset of UPFs - as Group 1 carcinogens, placing these foods in the same evidentiary category as tobacco and asbestos, while CDC data shows Americans consume over half of their daily calories from ultra-processed foods, on average.

Researchers have compared tactics to manufacture scientific doubt on UPFs to those used by the tobacco industry, noting that eight UPF manufacturers—Nestlé, PepsiCo, Unilever, Coca-Cola, Danone, Fomento Economico Mexicano, Mondelez, and Kraft Heinz—accounted for 42% of the sector's $1.5 trillion in assets in 2021.

6. Caveats and ongoing debate

Scientists and food industry groups caution that not all UPFs carry equal risk:

> Whether it's cooking, freezing, or fortifying with nutrients, the term 'processed' itself can be misleading when discussing health ... This paper underscores that not all ultra-processed foods (UPFs) are created equal, and grouping them together as universally detrimental is overly simplistic

> Not all processed foods are nutritionally equal – broad classifications risk oversimplifying the debate and overlooking nutritional nuance

Some food scientists reject the term "ultra-processed foods" because it suggests processing itself is harmful and creates misplaced dietary incentives.

Conclusion

Based on the largest umbrella review of 45 meta-analyses covering ~10 million people, plus dozens of prospective cohort studies and a controlled feeding trial showing increased intake and weight gain, major journals (The BMJ, The Lancet) and institutions (Harvard, CDC) now describe high UPF diets as consistently associated with 32 adverse outcomes - with convincing evidence for cardiovascular death, mental disorders, and type 2 diabetes, and with widespread, growing population exposure exceeding 50% of calories in high-income countries.

In that sense, leading researchers conclude these findings support urgent mechanistic research and public health actions that seek to target and minimise ultra-processed food consumption for improved population health, and call for tobacco-style regulation.

Other researchers argue for nuance: processing itself is not inherently harmful, risk varies dramatically by food type (sugary drinks and processed meats carry strongest signals; fortified whole-grain breads/cereals less so), and more high-quality interventional research is needed to separate the effects of processing from nutrient composition and to identify which UPF sub-categories drive harm before blanket policies are applied.