Are ultra-processed foods a public health hazard?

Yes — a substantial and rapidly growing body of scientific evidence indicates that ultra-processed foods (UPFs) represent a genuine public health hazard, though there's still debate about mechanisms and the strength of causal evidence for some outcomes.

What counts as "ultra-processed"

Under the widely used NOVA classification, ultra-processed food is defined as a group of foods that are industrial formulations created mostly or entirely from substances extracted from foods, with additives and with little if any intact food, such as fast foods, savory snacks, cakes, soft and/or sweetened drinks, and sausages. Examples include chips, frozen pizza, cereal, and other prepackaged, ready-to-eat items, which are typically high in sodium, sugar, and unhealthy fats and low in fiber and micronutrients.

Scale of exposure

This isn't a marginal issue — UPFs dominate modern diets. In the U.S., approximately 70% of packaged products in the U.S. food supply are foods often considered ultra-processed, and children get over 60% of their calories from such foods. Globally, this is also big business: global UPF sales grew from $1.5 trillion in 2009 to $1.9 trillion in 2023.

The observational evidence

Dozens of systematic reviews and meta-analyses of cohort studies have found consistent associations between UPF intake and disease risk. A major meta-analysis of nearly 200,000 people found that highest UPF consumption was associated with increased risk of all-cause mortality (RR 1.25), CVD (RR 1.29), cerebrovascular disease (RR 1.34), and depression (RR 1.20). Another large analysis found a consistently positive association between high UPF intake and increased risk of developing diabetes (37%), hypertension (32%), hypertriglyceridemia (47%), low HDL cholesterol (43%), and obesity (32%).

More specifically:

Moving beyond correlation: causal mechanisms

2025 was described as a turning point because growing evidence linking ultra-processed food consumption to chronic disease risk reached a point where experimental, clinical and epidemiological studies converged to elucidate underlying mechanisms. Notably, a 2025 randomized controlled trial showed harmful effects of UPFs on weight gain and metabolic and reproductive health, regardless of excessive caloric intake — suggesting it's not just about calories.

Researchers are also probing why UPFs are harmful beyond nutrient content: multiple factors are suspected to explain detrimental effects of UPFs, beyond their nutritional profile, including food additives. Animal studies add mechanistic support: an experimental study on mice found two widely consumed food additive emulsifiers caused transgenerational microbiota alteration that led to increased long-term susceptibility to metabolic and inflammatory diseases. In humans, a large prospective cohort study revealed positive associations between exposure to two widely consumed food additive mixtures and higher type 2 diabetes incidence.

A landmark UK crossover RCT (Dicken et al., Nature Medicine 2025) directly compared diets — this is one of the few trials that can speak to causality rather than mere association.

The counter-argument / caveats

The picture isn't unanimous. Some researchers caution that there is an ongoing debate on whether to advocate reducing ultra-processed food in dietary guidelines to control metabolic disease, and note an opposing view questioning the significance of UPF, suggesting that the concept and investigations of UPF are vague. Similarly, another meta-analysis acknowledged that risks varied significantly depending on the methodology used to assess UPF consumption, with a difference of more than 50% between methods, so caution should be used when interpreting and extrapolating results.

Equity dimension

UPFs also raise health-equity concerns: UPFs are frequently more affordable than less-processed foods, and their low cost and wide availability may drive health disparities among populations who already face hunger, undernutrition and higher rates of chronic disease. Similarly, underresourced communities are more prone to diets composed of UPF because of their affordability and accessibility, and are consequently disproportionately predisposed to negative health effects.

Policy response

Governments are beginning to treat this as a formal public health issue. In 2025, U.S. health agencies stated that dozens of scientific studies have found links between the consumption of foods often considered ultra-processed with numerous adverse health outcomes, including cardiovascular disease, Type 2 diabetes, cancer, obesity and neurological disorders, and announced plans to create a uniform definition of ultra-processed foods to allow for consistency in research and policy to address health concerns.

Bottom line

The weight of evidence — spanning large cohort studies, meta-analyses, and an increasing number of controlled trials — supports the conclusion that high UPF consumption is a meaningful public health hazard, contributing to obesity, type 2 diabetes, cardiovascular disease, certain cancers, kidney disease, and mental health issues. What remains actively debated is the precise causal mechanism (nutrient content vs. additives vs. food structure/texture vs. eating behavior) and how much risk is attributable to "ultra-processing" itself versus the poor nutritional quality that often accompanies it. Given the scale of UPF consumption in modern diets, most public health authorities now treat this as a priority issue rather than a settled non-concern.