Are ultra-processed foods a public health hazard?

I'll examine the latest evidence on ultra-processed foods and their impact on public health.

Yes, ultra-processed foods (UPFs) are increasingly regarded as a major and growing public health hazard, though the debate is nuanced.

What are ultra-processed foods?

UPFs are defined by the NOVA classification system, developed in Brazil in 2009, as industrial formulations containing additives like emulsifiers, sweeteners, and artificial flavorings that are not typically used in home cooking.

Researchers classify UPFs using the NOVA system, which categorizes items by their level of industrial processing. These products are defined as industrial formulations typically made with substances extracted from foods or synthesized in laboratories, and they often contain additives like colorings, flavorings and emulsifiers.

NOVA organizes foods into four groups:

Group one consists of unprocessed or minimally processed foods like fruits, vegetables, eggs and milk. Group two includes culinary ingredients such as salt, herbs, oils and the like. Group three are processed foods that combine groups one and two – canned goods and frozen vegetables are examples.

Group four are ultraprocessed foods, which are made flavourful and enticing by using combinations of artificial flavours, colours, thickeners and other additives.

They are formulations of often chemically manipulated cheap ingredients like modified starches, sugars, oils, fats, and protein isolates, with little if any, whole food added.

Examples include instant noodles, packaged snacks (e.g., chips, cookies), processed meats (e.g., hot dogs, burgers, chicken nuggets), instant soups, breakfast cereals and bars, soft drinks, ice cream, margarine, candy, sauces, and energy drinks.

How widespread is exposure?

UPFs already make up more than half of the total dietary energy consumed in high-income countries, such as the US, Canada, and the UK.

In the US:

Ultra-processed foods have been linked to the harming of every major organ system, and are described as fueling a "chronic disease pandemic."

Evidence of health risks

Researchers have found links between the consumption ultra-processed foods (UPFs) 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.

A landmark 2024 umbrella review published in The BMJ reviewed 45 meta-analyses covering nearly 10 million study participants.

The review found:
> Overall, direct associations were found between exposure to ultra-processed foods and 32 (71%) 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.

Based on pre-specified evidence classification, convincing evidence supported direct associations between greater ultra-processed food exposure and higher risks of:

A large analysis of 51 prospective cohort studies with 8,819,894 adults found:

The results suggested that eating a lot of ultra processed foods was associated with higher risks of cardiovascular events such as heart attack (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%).

And specifically:

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.

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.

Why are they harmful?

The causes are still being studied, but they are likely to occur because UPFs often have high amounts of added sugar, sodium, and saturated fat, and low amounts of fiber, vitamins, and minerals.

Other mechanisms include:

Is every UPF equally hazardous? The nuance

Not all experts agree that "ultra-processing" itself is inherently harmful.

UPF classifications capture many unhealthy foods, but they also sweep in items that are nutritionally sound or even beneficial.

This paper underscores that not all ultra-processed foods (UPFs) are created equal, and grouping them together as universally detrimental is overly simplistic.

The American Heart Association (AHA) suggests that not all ultra-processed foods (UPFs) are bad for you.

For instance, packaged whole grain breads, plant-based milks and some yogurts are considered ultra-processed, but they can be beneficial for health.

On the other hand, ultra-processed breads and cereals showed a negative association with the risk of contracting such diseases, meaning they were associated with lower risk, while sugary and artificially sweetened drinks and processed meats increased risk.

As one researcher summarized: "While many ultra-processed foods tend to be of poor nutritional quality and should generally be limited or avoided, processing itself is not inherently harmful".

A new scientific advisory from the American Heart Association has challenged the idea that all ultra-processed foods are unhealthy.

The Nova definition is geared toward research, to really examine the effects of ultra-processed foods on a range of health outcomes, but applying Nova can require individual-level review of ambiguous products by skilled nutrition experts that may not be feasible in policy contexts.

Due to this, a panel of 14 experts in 2025 proposed a more practical ingredient-based definition: if a product has just one marker ingredient (cosmetic or non-culinary industrial ingredient), then it is ultra-processed, while suggesting that if a product meets the FDA's criteria for a "Healthy" food, then it should be exempted from policy.

Public health response

The BMJ umbrella review authors concluded:

Greater exposure to ultra-processed food was associated with a higher risk of adverse health outcomes, especially cardiometabolic, common mental disorder, and mortality outcomes. These findings provide a rationale to develop and evaluate the effectiveness of using population based and public health measures to target and reduce dietary exposure to ultra-processed foods for improved human health.

Current policy developments include:

Recommendations from experts include requiring labels on packages identifying a product as ultra-processed and removing UPFs from food served in schools, childcare and in government facilities. Some US states like California have passed legislation to phase out ultra-processed foods in school meals.

Bottom line: While the evidence does not prove that every single UPF causes disease (observational studies cannot fully rule out confounding, and some UPFs like fortified whole-grain breads may be neutral or beneficial), the weight of evidence from nearly 10 million people shows consistent, dose-dependent associations between high UPF consumption — especially sugary drinks, processed meats, and salty/sugary snacks — and obesity, diabetes, cardiovascular death, mental disorders, and overall mortality. For this reason, major medical bodies and public health agencies are now treating high UPF diets as a public health hazard and are moving toward policies to reduce exposure.