Are ultra-processed foods a public health hazard?

Yes — the evidence increasingly points to ultra-processed foods (UPFs) as a genuine public health hazard, though with some important caveats about causality.

The scale of the evidence

The most comprehensive assessment to date is a 2024 umbrella review published in The BMJ, which pooled data from 45 meta-analyses covering roughly 10 million people. 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, published online Feb. 28, 2024, by The BMJ, come from a review of 45 analyses published in the last three years, involving about 10 million people in total.

The findings were striking: 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, while associations with asthma, gastrointestinal disease, some cancers, and other health issues were limited and need further investigation. Overall, this umbrella review of 45 meta-analyses including almost 10 million people found that diets high in UPFs are linked to 32 health conditions, including obesity, type 2 diabetes, cardiometabolic diseases, many cancers, gastrointestinal disorders, asthma, anxiety, depression, cardiovascular events, and all-cause mortality.

Specific risk estimates

Multiple large dose-response meta-analyses give concrete numbers:

The 2025 Lancet Series raises the stakes further

A major three-part Lancet Series (published November 2025) went further, arguing UPFs are displacing traditional diets worldwide and directly damaging nutrition quality. The series describes deterioration of diet quality, especially in relation to chronic disease prevention, confirmed by national food intake surveys, large cohorts, and interventional studies showing gross nutrient imbalances, overeating driven by high energy density, hyper-palatability, soft texture, and disrupted food matrices, reduced intake of health-protective phytochemicals, and increased intake of toxic compounds and endocrine disruptors.

The series' authors were blunt about the policy implications, stating that deteriorating diets are an urgent public health threat that requires coordinated policies and advocacy to regulate and reduce ultra-processed foods and improve access to fresh and minimally processed foods. They also argued that the science already shows enough harm to justify immediate public health action, and that waiting for perfect evidence would only allow UPFs to become even more entrenched in global diets. A systematic review conducted for this series, covering 104 long-term studies, found 92 reported greater associated risks of one or mo[re outcomes] associated with UPF consumption.

Important caveats — the evidence isn't airtight

Despite the alarming headlines, scientists urge caution:

Bottom line

The convergence of umbrella reviews, large-scale dose-response meta-analyses, and a major 2025 Lancet Series represents a substantial and mounting body of evidence that high UPF consumption is associated with numerous serious health harms — obesity, type 2 diabetes, cardiovascular disease, certain cancers, mental health disorders, and premature death chief among them. While the field still debates whether "processing" itself is the causal agent versus the poor nutritional composition typical of many UPFs, the sheer consistency and scale of the associations — spanning tens of millions of participants across dozens of countries — has been enough to convince many public health researchers and bodies like The Lancet's editorial teams that UPFs represent a genuine and pressing public health hazard warranting policy action now, rather than waiting for definitive causal proof.