Scientists have linked ultra-processed foods to the risk of chronic diseases

Every additional 100 grams of ultraprocessed food per day was associated with a 14% increased risk of cardiovascular events, 4% higher risk of cancer, 3% higher risk of death from any cause, and 2% higher risk of metabolic syndrome or diabetes. These conclusions were reached by the authors of a meta-analysis of 51 prospective studies involving almost 8.82 million adults. The article "Izvestia" describes which foods are considered ultra-processed, how they can affect the body and why the results do not prove a cause—and-effect relationship.

Which foods are considered ultra-processed

Ultraprocessed products include ready-to-eat or reheated products that undergo several stages of industrial processing and often contain flavors, colors, emulsifiers, sweeteners, and other additives. This category may include sugary drinks, chips, sweets, industrial biscuits, certain types of bread, meat products and ready meals.

At the same time, we are not just talking about any food that has been crushed, frozen or subjected to heat treatment. The NOVA classification divides products into four groups: unprocessed or minimally processed, processed culinary ingredients, processed foods, and ultraprocessed foods. The latter group is usually characterized by a complex industrial composition and the presence of components that are rarely used in an ordinary kitchen.

The authors note that such food often has a high energy density, contains a lot of sugar and salt, but little dietary fiber, protein, vitamins and minerals. However, the category is heterogeneous: the composition, nutritional value, and degree of processing of different products may vary significantly.

What did the data analysis of almost 9 million people show?

The researchers examined scientific papers published by the end of April 2026. The final analysis included 51 prospective cohort studies from the Americas, Europe, Asia, and Oceania. A total of 8,819,894 people participated in them, the average age of which ranged from 23 to 77 years in different samples. The follow-up lasted from two to 32 years.

Food intake was assessed using questionnaires on the frequency of food intake, daily diet surveys, and nutritional history records. To compare the results, the scientists translated data on the amount of ultraprocessed food into 50 g portions.

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The authors considered eight groups of outcomes: high blood pressure, cardiovascular events, cancer, metabolic syndrome or diabetes, digestive system diseases, overweight or obesity, depression or anxiety disorders, and death from any cause. Cardiovascular events included heart attack, stroke, transient ischemic attack, coronary heart disease, and death from cardiovascular causes.

When comparing people with high and low intake of ultra-processed foods, the association with diseases of the digestive system was most noticeable: the relative risk was 31% higher. The difference was 27% for depression and anxiety, 24% for cardiovascular events and metabolic syndrome or diabetes, and 23% for overweight and obesity.

High consumption was also associated with an increase in the relative risk of death from any cause by 18%, cancer by 12%, and high blood pressure by 11%. These indicators reflect the combined estimates of different studies, and the boundaries of high and low consumption in individual samples may have differed.

How did the risks change with each additional 100g

Separately, the researchers conducted a dose-dependent analysis. He showed that every additional 100 grams of ultraprocessed food per day was associated with a 14% increase in the relative risk of cardiovascular events. The increase was 4% for cancer, 3% for death from any cause, and 2% for metabolic syndrome or diabetes.

These percentages should not be added to the personal probability of getting sick. We are talking about relative, not absolute risk. For example, a figure of 14% indicates a difference between the compared groups relative to the baseline level, which depends on age, health status, and other factors. It does not mean that 14 out of every 100 people who eat an additional portion of such food will develop the disease.

In addition, 100 g is a measure of the weight of the entire category, not one standard serving or a specific product. The same amount of sugary drink, bread, and semi-finished meat products can vary markedly in terms of calories, sugar, salt, fat, and dietary fiber.

Another assessment method took into account the proportion of ultra-processed foods in the total weight or energy value of the diet. An increase in this proportion for every 10% was associated with a 16% increased risk of metabolic syndrome or diabetes.

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How food processing can affect the body

The authors named several possible mechanisms, but emphasized that they are still being studied. One of them is related to the combination of numerous dietary supplements. It is assumed that their combined effect may differ from the effect of each substance individually and create a so-called cocktail effect.

Significant processing changes the physical structure of food and can affect the rate of its consumption and assimilation. Laboratory data also indicate possible changes in the intestinal microbiome, the development of inflammation and a decrease in tissue sensitivity to insulin. However, these mechanisms do not prove that it was the degree of processing that caused all the identified connections in humans.

Individual potentially harmful compounds may form during industrial preparation. Among them, the researchers mentioned acrylamide, which occurs during high-temperature processing of carbohydrate-rich foods, and acrolein, which can form when fats are heated. Previously, these substances were associated with adverse effects on the cardiovascular system.

At the same time, part of the risk may be explained not by the treatment itself, but by the composition of the diet. People who eat a lot of these foods can get more calories, sugar, salt, and saturated fats, and less fiber and trace elements. Their lifestyle may also differ in terms of physical activity, smoking, alcohol consumption, sleep quality, and access to medical care.

Why don't the results prove a causal relationship?

All included works were observational. This means that the researchers compared the participants' habitual diets with subsequent diagnoses, but did not randomly assign people by type of diet. Therefore, the meta-analysis shows a stable statistical relationship, but by itself does not prove that ultraprocessed foods have become the direct cause of diseases.

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Another limitation is related to self-reports. Participants could inaccurately recall what and in what quantity they ate. In addition, food questionnaires do not always allow you to determine the method of production of the product. For example, artisan and industrial bread may be included in the same line of the questionnaire, although according to NOVA they will be classified into different groups.

Adam Jacobs, Executive Director and Consultant on biostatistics at Ergomed, noted in a comment from the Science Media Center that the sample size alone does not eliminate these problems.

Gunther Kuhnle, Professor of Dietetics and Food Sciences at the University of Reading, also pointed out the ambiguity of the definition of ultra-processed foods and the lack of detail in the methods of assessing the diet. According to him, products with different compositions and already known health effects can fall into one broad category, so it is not always clear what role industrial processing itself plays.

The researchers additionally noted that the analysis did not include participants under the age of 18. In addition, diet-related diseases often develop simultaneously and depend on a variety of social, behavioral, and medical factors that are difficult to fully account for statistically.

The authors believe that reducing the proportion of ultra-processed foods and replacing them with minimally processed foods can be used in the prevention of chronic diseases. However, the results do not establish a universal safe norm in grams and do not allow assessing individual risk without taking into account the entire diet and human health status.