Consumption of ultra-processed foods contributes to the increase in chronic diseases

What's this about?

People disagree about whether eating more ultra-processed foods helps cause long-term health problems.

These foods often use many factory steps, added sugar, salt, or unhealthy fats.

What supporters say

• Studies that track people for years show that those who eat more of these foods often face more heart disease, cancer, and early death.
• These foods can lower diet quality by adding more calories, salt, sugar, and bad fats while replacing healthier foods.
• A small food trial found that people ate more and gained weight on an ultra-processed diet, which may raise later disease risk.

What critics say

• Most studies only watch what people eat, so they cannot prove that these foods caused the diseases.
• The food label “ultra-processed” may group together foods with very different health risks.

How to read this

The number of points on each side does not show who is right; the strength of the proof matters more.

The bottom line

The evidence suggests that ultra-processed foods likely add to the rise in long-term diseases, but they are not the only cause.

The link appears steady, yet much of the proof comes from studies that cannot fully prove cause and effect.

The claim is not that every ultra-processed food is harmful, or that these foods alone explain rising chronic disease. The question is whether eating more of them contributes to disease at the population level.

The case for

Large prospective studies show a repeated pattern: people who eat more ultra-processed food tend to face higher risks of several chronic conditions. These include cardiovascular disease, death from any cause, and cancer–cardiometabolic multimorbidity. An umbrella review found links with 32 of 45 adverse health outcomes, including mortality and metabolic and heart-related conditions, although most of the pooled evidence was rated low or very low quality. 1 (see Figure 1)

The pattern is therefore consistent, but it does not look identical for every product. A multinational study found that the strength of the association varied between food subgroups, suggesting that some ultra-processed foods may matter more than others.

A small controlled trial offers a possible pathway through obesity. In a randomized inpatient study of 20 adults, participants ate about 500 more calories per day and gained weight while following an ultra-processed diet than while eating an unprocessed diet. The trial was short, involved few people, and the diets differed in ways beyond processing. Still, because excess body weight raises the risk of diabetes, cardiovascular disease and some cancers, the findings support one route by which these dietary patterns could contribute to later disease. 2

Ultra-processed foods may also damage health indirectly by lowering the quality of the overall diet. Food and health-policy reviews describe diets high in these products as typically containing more calories, sodium, free sugars and unhealthy fats, and fewer minimally processed foods. Those are established dietary risk factors for chronic disease. The evidence here comes from dietary patterns and syntheses rather than trials that prove cause and effect. 3 (see Figure 2)

The case against

The main objection is causal attribution. Most evidence linking ultra-processed food with disease comes from observational studies. Such studies can show that two things occur together, but they cannot fully establish that one caused the other. Differences in income, health behavior, education, existing health and other factors may partly explain the results. Researchers also face errors in measuring what people eat and difficulty separating food processing from overall diet quality. 4

The NOVA category itself creates another problem. It groups together a wide range of products with different ingredients, nutritional profiles and uses. Critical reviews argue that the apparent risks may be driven mainly by particular products—such as sugary drinks, processed meats or energy-dense snacks—or by their high calorie content, rather than by industrial processing as an independent cause. Findings from the EPIC study, which showed different results across food subgroups, support this caution. 5

The evidence is more convincing for obesity-related and cardiometabolic risk than for every chronic disease. Associations with individual cancers and several other conditions are less certain, and cancer reviews have relied largely on varied observational studies. Possible explanations include high palatability, rapid eating, food structure, additives, packaging and the displacement of healthier foods, but research has not established which mechanism matters most.

The bottom line

Overall, the evidence favours the claim, but only in a qualified population-level sense. Greater consumption of ultra-processed food consistently tracks with chronic-disease risk, and a controlled trial supports increased calorie intake and weight gain as one plausible pathway.

However, the evidence is much stronger for an epidemiological signal than for proof that processing itself causes disease across the entire category. Long-term randomized studies that separate processing from nutrients, calorie density and broader diet are lacking. The key uncertainties are how much risk comes from processing itself, which products drive the associations, and whether the pattern applies equally to all diseases and populations.