Are ultra-processed foods a public health hazard?

Ultra-processed foods are under intense scrutiny — I'll gather the latest evidence on their health risks.

Yes — the majority of major reviews and public health bodies now describe diets high in ultra-processed foods (UPFs) as a public health hazard, while noting nuance and gaps in evidence.

1. What counts as ultra-processed?

The term is most commonly associated with the NOVA classification system:

> Ultra-Processed Foods (UPF; NOVA "Group 4") refers to "industrial formulations made entirely or mostly from substances extracted from foods (oils, fats, sugar, starch, and proteins), derived from food constituents (hydrogenated fats and modified starch), or synthesized in laboratories"

A more detailed definition includes:

> "industrial formulations made entirely or mostly from substances extracted from foods (oils, fats, sugar, starch, and proteins), derived from food constituents (hydrogenated fats and modified starch), or synthesized in laboratories from food substrates or other organic sources (flavor enhancers, colors, and several food additives used to make the product hyperpalatable)"

Examples include packaged baked goods and snacks, fizzy drinks, sugary cereals, and ready-to-eat or heat products, which often contain colors, emulsifiers, flavors, and other additives. They also tend to be high in added sugar, fat, and/or salt, but are low in vitamins and fiber.

A common NOVA shorthand sums it up as "snacks, drinks, ready meals and many other products created mostly or entirely from substances extracted from foods or derived from food constituents with little if any intact food."

2. How widespread is consumption?

Exposure is already very high in high-income countries and rising in low and middle-income nations:

3. What does the evidence show?

Consistent epidemiological association

> 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.

There is evidence that people who eat more ultra-processed foods have a higher risk of a wide range of health problems, including obesity, heart disease, type 2 diabetes and some cancers.

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.

Overall, evidence consistently links high consumption of ultra-processed foods with increased cardiovascular disease risk, supported by epidemiological studies and NF-κB-driven inflammatory mechanisms

Largest review to date

The most comprehensive assessment was an umbrella review published Feb 28, 2024 in The BMJ:

> 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. The findings, 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

> Researchers carried out an umbrella review (a high-level evidence summary) of 45 distinct pooled meta-analyses from 14 review articles associating ultra-processed foods with adverse health outcomes

> The review articles were all published in the past three years and involved almost 10 million participants

> 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.

> Overall, the results show that higher exposure to ultra-processed foods was consistently associated with an increased risk of 32 adverse health outcomes.

> The findings show that diets high in ultra-processed food may be harmful to many body systems

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

In detail:

> Convincing evidence showed that higher ultra-processed food intake was associated with around a 50% increased risk of cardiovascular disease-related death, a 48-53% higher risk of anxiety and common mental disorders, and a 12% greater risk of type 2 diabetes.

> Highly suggestive evidence also indicated that higher ultra-processed food intake was associated with a 21% greater risk of death from any cause, a 40-66% increased risk of heart disease-related death, obesity, type 2 diabetes, and sleep problems, and a 22% increased risk of depression.

Evidence for associations with asthma, gastrointestinal health, some cancers, and cardiometabolic risk factors, such as high blood fats and low levels of 'good' cholesterol, remains limited.

Other pooled analyses of ~8-9 million adults report similar magnitudes:

> 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%).

> People with the highest UPF consumption had a: - 24% higher risk of cardiovascular events like heart attacks and strokes - 23% higher risk of obesity or overweight

> Higher consumption of ultra-processed foods was associated with a 24% greater risk of cardiovascular events, 12% higher cancer risk and 23% higher risk of overweight or obesity.

Dose-response and mechanistic data strengthen concern: clinical trials show that people who consume a diet high in ultra-processed foods tend to overeat and gain unwanted weight, and research has linked high UPF intake spending 57.9% of food budget on such foods to overeating mechanisms engineered with specific ratios of fat, salt and sugarthough formal "food addiction" is not recognized by DSM-5 or WHO.

Authors conclude:

> These findings support urgent mechanistic research and public health actions that seek to target and minimize ultra-processed food consumption for improved population health.

> Findings underscore need for urgent research to understand how ultra-processed foods affect health and measures to target and reduce exposure.

4. Public health response

Public health authors argue reformulation does not eliminate harm, and profitability discourages manufacturers from switching to make nutritious foods, so public policies and action on ultra-processed foods are essential.

Proposed measures include:

> front-of-pack labels, restricting advertising and prohibiting sales in or near schools and hospitals, and fiscal and other measures that make unprocessed or minimally processed foods and freshly prepared meals as accessible and available as, and cheaper than, ultra-processed foods.

An editorial accompanying the BMJ review argued:

> It is now time for United Nations agencies, with member states, to develop and implement a framework convention on ultra-processed foods similar to the framework on tobacco

The WHO is developing guidance:

> Recommendations to limit UPFs in national dietary guidelines
>
> WHO said that it would present a profiling model for regulatory measures on ultra-processed foods by the end of 2026 and guidelines on consumption by 2028.

National guidelines increasingly reflect this, e.g. recommending limiting "highly processed packaged, prepared, ready-to-eat, or other foods that are salty or sweet" and encouraging meals built around whole, minimally processed foods.

5. Nuance and debate

Not all scientists agree that UPF as a NOVA category equals "unhealthy":

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

> But not all foods that fit the definition of ultra-processed are unhealthy, says Julia Wolfson, an associate professor at the Johns Hopkins Bloomberg School of Public Health. For instance, packaged whole grain breads, plant-based milks and some yogurts are considered ultra-processed, but they can be beneficial for health.

Other studies have found ultra-processed whole grain breads are linked to a lower risk of Type 2 diabetes and cardiovascular disease.

Experts also note:

> Debates about ultra-processed foods focus on their potential links to health issues—as well as the role of misinformation and context: not all ultra-processed foods are equally unhealthy, and access or food security are important factors.

Key limitations cited in the literature are that most data are observational (cannot fully prove causation, residual confounding), UPF is a heterogeneous category, and nutritional quality varies widely within it. The BMJ authors themselves noted umbrella reviews can only provide high-level overviews and they can't rule out the possibility that other unmeasured factors and variations in assessing ultra-processed food intake may have influenced their results.

Bottom line

Reducing UPF intake, especially of sugary drinks, processed meats, salty snacks, confectionery and ready meals, and replacing them with less-processed or whole foods is the most supported public-health recommendation.