Are ultra-processed foods a public health hazard?

Ultra-processed foods and public health — I'll pull the latest evidence and expert guidance on the risks.

Yes - the current scientific consensus is that high consumption of ultra-processed foods (UPFs) is an emerging major public health hazard, with calls from The BMJ, The Lancet and WHO-affiliated researchers for urgent public health action, even as debate continues about mechanisms and causality.

1. What are ultra-processed foods?

There is no single legally accepted definition, but the most used framework is the NOVA classification, developed by Monteiro and colleagues in 2010.

NOVA categorizes foods into four groups by type, intensity and purpose of processing:

UPFs are described as “industrial formulations with five or more ingredients” that contain substances not typically used in culinary preparations, or as industrial formulations made entirely or mostly from substances extracted from foods (oils, fats, sugar, starch, proteins), derived from food constituents (hydrogenated fats, modified starch) or synthesized in laboratories.

More specifically, the ultra-processed group includes all foods and drinks made using intense physical or chemical processes or containing cosmetic food additives and other industrial ingredients (e.g., artificial flavours, hydrogenated oils, glucose/fructose corn syrup).

This includes products that contain industrial substances not usually found in domestic kitchens (e.g., maltodextrin, hydrogenated oils, or modified starches), cosmetic additives (e.g., dyes, emulsifiers, artificial sweeteners), or flavouring agents. Examples include carbonated soft drinks, chocolate and energy bars, instant noodles, dehydrated soups, fish and chicken nuggets, powdered or “fortified” meals, and meat substitutes containing protein isolates, plus packaged baked goods and snacks, fizzy drinks, sugary cereals, and ready-to-eat or heat products, which often contain colours, emulsifiers, flavours and other additives. They also tend to be high in added sugar, fat, and/or salt, but are low in vitamins and fibre.

Not all processing is equivalent. Frozen vegetables are “processed” but healthy, whereas a neon-colored snack cake is “ultra-processed”, and pasteurized milk is processed to enhance shelf life but not considered ultra-processed.

2. How widespread is exposure?

They 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 in recent decades.

National survey data show wide variation: highest intake is in the United States (58% of daily energy) and the lowest in Colombia (16%). Within Europe intake ranges from 15% of total calories in Romania to 57% in the UK. Since the 1990s sales have either been increasing (mainly in low and middle income countries) or stayed high.

3. How strong is the evidence for harm?

Large-scale epidemiological evidence

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.

Researchers have also found links with obesity, cancer, heart disease, type 2 diabetes, and mental disorders, as well as an increased risk of death. A 2024 review from the British Medical Journal of 45 meta-analyses, covering nearly 10 million study participants, found “convincing” evidence that a diet high in UPFs increases risk.

The most comprehensive assessment to date is a 2024 umbrella review in The BMJ:

> Researchers carried out an umbrella review of 45 distinct pooled meta-analyses from 14 review articles associating ultra-processed foods with adverse health outcomes. The review articles were all published in the past three years and involved almost 10 million participants. None were funded by companies involved in the production of 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.

Overall, higher exposure to ultra-processed foods was consistently associated with an increased risk of 32 adverse health outcomes.

When scientists graded 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.

Specifically:

Other meta-analyses summarized:

Compared with people with low consumption, those with the highest consumption have been shown to have higher risks of type 2 diabetes, hypertension, overweight or obesity, cardiovascular and cerebrovascular events, as well as all-cause and cardiovascular mortality.

Cohort studies have also associated UPFs with several cancers, inflammatory bowel disease, depression, gestational diabetes, and chronic kidney disease.

Dose-response analyses indicate each 100 g/day increase in UPF intake was linked to a 3% higher risk of frailty, and more broadly high consumption 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 2025 analysis in JAMA Oncology found women who consumed about 10 servings per day had a 45% higher risk of developing precancerous colorectal polyps compared to those who ate about three servings per day.

People who eat more ultra-processed foods also experience higher risk for obesity, heart disease, type two diabetes and some cancers.

Experimental evidence

Beyond observational studies, researchers have conducted clinical trials showing that people who consume a diet high in ultra-processed foods tend to overeat and gain unwanted weight.

One crossover trial allocated participants to an ultra-processed or unprocessed diet for two weeks each and found that the ultra-processed diet led to increased energy intake and weight gain, while the unprocessed diet resulted in lower energy intake and weight loss.

4. Why might they be hazardous? Multifaceted mechanisms

Experts argue incomplete understanding of multiple mechanisms should not be an excuse for inaction, but several converging pathways have been identified:

a) Poor nutrient profile and displacement of healthy foods: Diets with large amounts of UPFs are on average poorer, containing more added sugars, refined grains, saturated fat, sodium, energy density, and less fibre, protein, and micronutrients. UPFs are energy-dense but nutrient-poor, delivering high calories with low nutritional value and displace minimally processed, nutritious foods such as fruit, vegetables, legumes, nuts, and seeds, thereby limiting intake of plant based bioactive compounds such as polyphenols. They are described as engineered for taste and convenience, not nutrition, often packing high levels of sugar, salt, and unhealthy fats while stripped of fiber.

b) Additives and microbiome disruption: There are unhealthy additives to change texture, color, sweetness, or flavor. These additives disrupt the microbiome in the gut and can lead to gut inflammation, including production of metabolites that can affect brain function and leaky gut, allowing toxins to enter the bloodstream. Industrial additives — including emulsifiers, artificial sweeteners, and flavor enhancers — may disrupt digestion, metabolism, and even the gut microbiome. Many additives act like detergents in the gut, stripping away the protective mucus layer and triggering inflammation.

The many food additives (e.g., sweeteners, colorants, preservatives, thickeners, and emulsifiers) may also have detrimental effects on health, both through single exposures and cocktail effects. Direct biological effects of additives, altered food structures, and production of harmful byproducts and systematic displacement of minimally processed, protective foods have been proposed.

c) Food matrix and hyper-palatability: Changes to the food matrix during processing may affect satiety, transit time, digestibility, and absorption kinetics. Harmful attributes co-occur systematically including disrupted food matrices and excessive energy density that accelerate eating and increase energy intake; engineered hyper-palatable formulations that override satiety signals. “Bliss point” engineering fosters compulsive overeating, with studies showing UPFs are consumed 500 calories more per day on average than unprocessed foods.

d) Toxicants and contaminants: Food processing can produce potentially toxic compounds such as furans, heterocyclic amines, polycyclic aromatic hydrocarbons, acrolein, advanced glycation end products, industrial trans-fatty acids, and acrylamide. With long shelf life, migration of contaminants such as phthalates, bisphenols, mineral oils, and microplastics from contact packaging may have carcinogenic properties and increase risk of cardiovascular disease, obesity, insulin resistance, and type 2 diabetes.

Importantly, findings suggest ultra-processed-food factors beyond nutrients—such as changes to foods' cellular structure, loss of beneficial chemical compounds, additives, and chemicals from packaging—may create health risks not addressed by traditional nutrition metrics.

5. Limitations and nuance

6. Public health implications

Authors conclude findings support urgent mechanistic research and public health actions that seek to target and minimise ultra-processed food consumption for improved population health.

The Lancet Series authors call diets high in UPFs associated with increased risk of multiple chronic diseases and call for governments to consider a broad package of measures, including tighter marketing restrictions, front-of-pack labelling, fiscal policies and healthier school food environments.

Proposed actions include:

This change in what people eat is fuelled by powerful global corporations who generate huge profits by prioritising ultra-processed products, supported by extensive marketing and political lobbying to stop effective public health policies.

Bottom line

This summary is for information and does not constitute medical advice. If you have concerns about diet and disease risk, discuss with a healthcare professional or registered dietitian.