Are ultra-processed foods a public health hazard?

Ultra-processed foods' health impact is under intense scrutiny — I'll pull the latest evidence on whether they amount to a public health hazard.

Yes - according to the majority of recent large-scale evidence reviews, ultra-processed foods (UPFs) are increasingly described as a major public health hazard, though there is active scientific debate about nuance and classification.

1. What counts as ultra-processed?

Under the NOVA classification system, widely used in research:

•UPFs are defined as “industrial formulations with five or more ingredients” that contain substances not typically used in culinary preparations.

•Examples include carbonated soft drinks or instant noodles, as well as cakes, cookies, energy drinks, chips, and sweetened juices.

•They are ready-to-eat products such as deli meat, microwaveable dinners, or chips with long ingredient lists, with lots of additives such as preservatives, oil, sugar, salt, coloring, and flavoring.

2. What the evidence shows

Researchers have found links between the consumption of ultra-processed foods and a range of negative health outcomes, including obesity, cancer, heart disease, type 2 diabetes, and mental disorders, as well as an increased risk of death.

Large umbrella reviews:

•A 2024 review from the British Medical Journal (BMJ) of 45 meta-analyses, covering nearly 10 million study participants, found “convincing” evidence that a diet high in UPFs increases the risk of death.

•The review 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 with asthma, gastrointestinal disease, some cancers and other health issues were limited and need further investigation.

•Overall, direct associations were found between exposure to ultra-processed foods and 32 health parameters spanning mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic health outcomes.

•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.

•An international analysis pooling data on 8,819,894 adults from 51 prospective cohort studies found those who consumed higher levels of UPFs were more likely to develop cardiovascular disease, cancer and diabetes. 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%).

The 2025 Lancet Series:

In November 2025, The Lancet published a three-paper series bringing together 43 global experts:

> “The rise of ultra-processed foods (UPFs) in human diets is damaging public health, fuelling chronic diseases worldwide, and deepening health inequalities.”

•The series reviewed more than a hundred studies which have linked ultraprocessed foods to poor health outcomes, including an increased risk of Type 2 diabetes, obesity, chronic kidney and heart disease, even depression.

•In a systematic review of 104 long-term studies done for the series, 92 reported greater associated risks with one or more chronic diseases linked to UPF dietary patterns, and significant associations for 12 health conditions including Type 2 diabetes, obesity and depression.

•One author stated: “We can say now that truly ultraprocessed food represents a clear global threat to our health - not only our physical health but also mental health in terms of its impacts on depression.”

The authors noted consumption of UPFs is rising worldwide as a share of the diet, to above 50% in countries like the United States.

3. Why they may be harmful - proposed mechanisms

Authors argued UPFs cause a deterioration of diet quality, not just because they are commonly high in fat, salt and sugar (HFSS), but also that they are hyperpalatable, low in health-protective phytochemicals.

Other mechanisms cited include:

•Gut microbiome disruption: Additives and altered textures starve healthy bacteria, favor inflammation, and weaken gut lining

•Contaminants and additives: Emulsifiers, artificial colors, preservatives can alter metabolism, induce inflammation, and potentially increase carcinogenic risk

Researchers have theorized inflammation occurs because UPFs are recognized by the body as foreign – much like invading bacteria, and additives like emulsifiers and artificial sweeteners increase inflammation by changing the gut microbiome.

4. Is it the processing itself? Debate and nuance

Most of these studies were only designed to show links, rather than direct causality, which the authors acknowledged.

The authors acknowledge criticisms in the Lancet series, saying more evidence is needed, particularly on why and how UPFs cause ill health, as well as on products with different nutritional values within the UPF class.

Critics and even the food industry argue:

•A scientific advisory from the American Heart Association (AHA) has challenged the idea that all ultra-processed foods are unhealthy. Ultra-processed foods have developed an unhealthy reputation, but not all UPFs are created equally.

•Not all foods that fit the definition of ultra-processed are unhealthy. For instance, packaged whole grain breads, plant-based milks and some yogurts are considered ultra-processed, but they can be beneficial for health.

•A Harvard analysis found that sugary and artificially sweetened drinks and processed meats increased the risk of heart disease, but that bread, cold cereals, even some savory snacks, had beneficial effects.

•Some researchers argue UPF classifications capture many unhealthy foods, but they also sweep in items that are nutritionally sound or even beneficial, and “The current evidence base simply does not support the idea that ‘ultraprocessing’ itself is a meaningful biological exposure.”

The International Food and Beverage Alliance said “The policy and advocacy recommendations of this series go far beyond the available evidence,” arguing there was a risk of reducing the availability of affordable, shelf-stable options globally.

5. Public health implications

Because the signal is already considered strong enough for governments to take action, the Lancet authors called for policies similar to those used against Big Tobacco, such as taxes on sodas, warning labels on packaged foods, a ban on marketing these foods to kids and removing ultraprocessed foods from big institutions like schools and hospitals.

Recommended individual steps in Harvard Health and other reviews include cutting UPFs out as much as possible and replacing them with less-processed options or whole foods.

Bottom line: Leading international bodies now call UPFs a danger to global public health based on consistent associations with at least a dozen chronic conditions, but the hazard is driven primarily by certain subcategories - sugary drinks, processed meats, salty snacks and ready meals high in sugar, salt and saturated fat - rather than every item classified as NOVA 4. The strength of causality, and whether ultra-processing per se beyond poor nutrient profile and additives is harmful, remains under investigation.

Citations (3)

1srnnews.comNot yet classified
Ultra-processed foods are danger to global public health, experts warn - SRN News
Backs: “UPFs are defined as “industrial formulations with five or more ingredients” that contain substances not typically used in culinary preparations.”
2harvard.eduAcademic
More evidence that ultra-processed foods harm health
Backs: “UPFs are defined as “industrial formulations with five or more ingredients” that contain substances not typically used in culinary preparations. Examples include carbonated soft drinks or instant noodles, as well as cakes, cookies, energy drinks, chips, and sweetened juices. They are ready-to-eat products such as deli…”
3nprillinois.orgNews and media
Ultra-processed foods are a threat to public health, scientists say
Backs: “In a systematic review of 104 long-term studies done for the series, 92 reported greater associated risks with one or more chronic diseases linked to UPF dietary patterns, and significant associations for 12 health conditions including Type 2 diabetes, obesity and depression. One author stated: “We can say now that…”