Are ultra-processed foods a public health hazard?
The PMC meta-analysis and Harvard Health link UPFs to many harms, while Harvard Magazine argues the UPF category is overbroad and may misclassify nutritious foods.
Ultra-processed foods are under intense scrutiny — I'll gather the latest evidence on whether they pose a public health hazard.
Are ultra-processed foods (UPFs) a public health hazard? Major scientific bodies increasingly say yes - but with important nuances.
1. What counts as ultra-processed?
According to the NOVA classification, the most widely used system, UPFs are formulations of ingredients, mostly for industrial use only, derived from a series of industrial processes.
In practical terms:
> They're ready-to-eat products such as deli meat, microwaveable dinners, or chips. They typically have long ingredients lists, with lots of additives such as preservatives, oil, sugar, salt, coloring, and flavoring
Examples given in the literature include breakfast cereals, savoury snacks, reconstituted meat products, frankfurters, pre-packaged frozen dishes, soft and/or sweetened drinks, distilled alcoholic beverages and supplements.
UPFs represent a growing part of the global food supply, accounting for about 50–60 % of the energy content in the usual diet of the average US, Canadian or British consumer. Within the UK alone 56.8%–63.4% of energy intake comes from food that would be classified as ultraprocessed (NOVA 4).
2. The epidemiological evidence for harm is large and growing
The strongest evidence to date comes from an umbrella review published Feb. 28, 2024 in The BMJ:
> a review of 45 analyses published in the last three years, involving about 10 million people in total found 32 of them health problems noted.
> direct associations between exposure to ultra-processed foods and 32 health parameters including mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic ill health
> 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
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 and need further investigation.
Specific graded risks from the umbrella review:
> 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; low), heart disease related mortality (hazard ratio 1.66, 1.51 to 1.84; low), type 2 diabetes (odds ratio 1.40, 1.23 to 1.59; very low), and depressive outcomes (hazard ratio 1.22, 1.16 to 1.28; low)
A prior systematic review and meta-analysis of 23 studies (10 cross-sectional, 13 prospective cohorts) found:
highest UPF consumption was associated with a significant increase in the risk of overweight/obesity (+39 %), high waist circumference (+39 %), low HDL-cholesterol levels (+102 %) and the metabolic syndrome (+79 %)highest UPF consumption was found to be associated with increased risk of all-cause mortality in five studies (risk ratio (RR) 1·25, 95 % CI 1·14, 1·37; P < 0·00001), increased risk of CVD in three studies (RR 1·29, 95 % CI 1·12, 1·48; P = 0·0003), cerebrovascular disease in two studies (RR 1·34, 95 % CI 1·07, 1·68; P = 0·01) and depression in two studies (RR 1·20, 95 % CI 1·03, 1·40; P = 0·02)Other cohort findings are consistent:
> those who ate the most ultra-processed foods had a 17% higher chance of developing cardiovascular disease compared with those who ate the least
> Processed meat was the type of food most strongly associated with increased mortality, while Sugar- and artificially sweetened beverages, dairy-based desserts, and ultra-processed breakfast foods also showed associations with higher all-cause mortality
The authors of the BMJ umbrella review concluded Findings underscore need for urgent research to understand how ultra-processed foods affect health and measures to target and reduce exposure.
3. Why would they be hazardous?
Several plausible, overlapping pathways are proposed:
a) Poor nutrient profile: Participants in the highest quartile of UPF intake consumed higher amounts of total energy, total fat, saturated fat and added sugar, and lower amounts of protein, micronutrients and fibre. This aligns with the broader concern that these foods tend to be high in sodium, sugar, and unhealthy fats.
b) Processing itself: Beyond nutrients, researchers are debating what's driving those risks: the nutritional quality of these foods—which are often high in refined grains, sodium, and added sugars—or the industrial processing and additives used to make them. Some studies found people who ate more ultra-processed foods had worse health outcomes, even after accounting for the overall nutritional quality of the foods, suggesting additives, neo-formed contaminants, altered food matrix, and hyper-palatability may play independent roles.
Editorials have argued this is sufficient for action:
> Mounting evidence from epidemiological studies links consumption of ultra-processed food to poorer cardiometabolic health and Existing evidence is sufficiently strong to warrant immediate public health actions to help citizens identify ultra-processed foods and limit their exposure
4. Important criticisms and nuance
The science is not unanimous that all NOVA-defined UPFs are inherently harmful.
In stark contrast to conventional systems for food classification, the NOVA system disregards the nutritional values of foods and many aspects of food processing can affect health outcomes, but conflating them into the notion of ultra-processing is unnecessary, because the main determinants of chronic disease risk are already captured by existing nutrient profiling systems.UPF classifications capture many unhealthy foods, but they also sweep in items that are nutritionally sound or even beneficial. For example, a food need have only one main ingredient or additive absent from traditional home cooking to earn ultraprocessed status—potentially causing misclassification and confusion. He notes that the category now includes many everyday items such as store-bought whole-grain breads, tofu, cheese, beef patties, and even sparkling water—since carbonation alone qualifies as a chemical additive. Indeed, some UPF subtypes like sugar- ... certain dairy products demonstrate neutral or protective effects. The binary nature of NOVA's classification may hide that heterogeneity.
Nova's UPF definition ignores the macronutrient content of foods, and "by disregarding nutrients, we throw out the baby with the bathwater." The UK's Scientific Advisory Committee on Nutrition has described the link as concerning but said it remains unclear whether the risk stems from the processing itself or from the fact many of these foods are high in fat, sugar and salt.tend to have less education and higher body weight, be more sedentary, smoke more, and drink more. All these factors are established risk factors for disease, independent of UPFs, making confounding difficult to fully remove. There are no long-term randomized controlled trials proving causation for chronic disease.Experts therefore caution against treating the label ultra-processed is being used interchangeably with unhealthy.
5. Public health view
Despite debate over definitions, most public health agencies now treat high UPF consumption—particularly of sugary drinks, processed meats, salty snacks, and sugary cereals—as a public health hazard:
advise the reduction or avoidance of 'ultra - processed foods' (UPF), a category of foods described within the NOVA classification system within national dietary guidelines based on evidence, largely from observational studies, linking high intakes of UPF with poor health outcomes including heart disease, type 2 diabetes, obesity and cancer.Multidisciplinary research, independent of industry, is needed to re-evaluate the safety of food additives and industrially processed ingredients as well as process related contaminants and for public health measures to target and reduce dietary exposure to the most harmful UPF subgroups.In practical terms, guidance does not require eliminating every food technically classified as ultra-processed, but rather:
anything salted, cured, smoked, or fermentedthem with less-processed options or (best of all) whole foodsBottom line: Based on consistent associations across ~10 million people linking high UPF exposure to 32 adverse outcomes—especially cardiovascular death, type 2 diabetes, obesity, depression and all-cause mortality—high UPF diets are widely considered an emerging public health hazard. The hazard is strongest and most consistent for a subset of UPFs high in added sugar, sodium and unhealthy fats and for overall diets where UPFs displace nutrient-dense foods. Whether processing per se beyond poor nutrient profile is causal, and whether every NOVA-classified UPF is hazardous, remains an active scientific debate.
Citations (3)
- Consumption of ultra-processed foods and health status: a systematic review and meta-analysis - PMC
Backs: “Are ultra-processed foods (UPFs) a public health hazard? Major scientific bodies increasingly say yes - but with important nuances. 1. What counts as ultra-processed? According to the NOVA classification, the most widely used system, UPFs are formulations of ingredients, mostly for industrial use only, derived from a…”
evidence, reference entry, points to yes. Claim: Major scientific bodies increasingly say UPFs are a public health hazard; meta-analysis links high UPF intake to obesity, metabolic syndrome, mortality, CVD and depression.
- More evidence that ultra-processed foods harm health - Harvard Health
Backs: “According to the NOVA classification, the most widely used system, UPFs are formulations of ingredients, mostly for industrial use only, derived from a series of industrial processes. In practical terms: They're ready-to-eat products such as deli meat, microwaveable dinners, or chips. They typically have long…”
background, article, points to yes. Claim: UPFs are ready-to-eat products like deli meat, microwaveable dinners or chips, with long ingredient lists and many additives.
- Is Ultraprocessed Food Really That Bad? | Harvard Magazine
Backs: “For example, a food need have only one main ingredient or additive absent from traditional home cooking to earn ultraprocessed status—potentially causing misclassification and confusion. He notes that the category now includes many everyday items such as store-bought whole-grain breads, tofu, cheese, beef patties, and…”
evidence, article, points to no. Claim: The UPF category includes nutritionally sound items like whole-grain bread, tofu, cheese and sparkling water, causing misclassification and confusion.