Ultra-processed foods have become an increasingly large part of the diet of many people globally.[1] Foods and beverages contact a diverse array of food contact materials and articles (FCMs and FCAs) as they travel from farm to fork, including processing equipment, packaging, and cookware. At each step along the supply chain, substances from FCMs and FCAs, known as food contact chemicals (FCCs), can migrate into foodstuffs.[2] Due to the extra steps involved in creating ultra-processed foods, they can acquire a significantly higher synthetic chemical burden, leading to increased downstream effects on health.
What are ultra-processed foods?
The term Ultra-Processed Food (UPF) is usually applied to a category of food products that have undergone extensive industrial processing, and often contain multiple ingredients and additives that one wouldn’t typically find in a home kitchen or traditional cooking. These foods are characterized by their convenience, long shelf-life, and sensory appeal, often engineered to be hyper-palatable. UPFs are usually low in whole food ingredients while high in sugars, saturated fats, salt, and synthetic additives like preservatives, colorings, flavorings, and emulsifiers.
Classifying ultra-processed food
A universally accepted definition of “ultra-processed food” or a protocol for classifying which foods are ultra-processed is still missing which makes comparisons between studies on UPFs difficult.[3] Common to all food classification systems outlined here is that they are based on the foodstuff’s degree of processing, formulation, and/or intended use.
Research by de Araújo et al. in 2022 found that the “inconsistencies among classifications were huge and the contribution from highly/[ultra processed foods] presented high discrepancies.”[4] They warn that “caution must be taken” when trying to compare studies using different systems and even interpreting any results.
NOVA
NOVA was developed by academic scientists in Brazil in 2019. It categorizes foods based on the extent and purpose of their processing.[5] Though applications can still vary,[6] it is widely used in nutrition science to better understand the health implications of different types of food.[7],[8],[9],[10],[11]
Group 1: Unprocessed or Minimally Processed Foods
These foods are typically “whole” foods that retain their nutritional properties and are close to their original state. Minimal processing might include cleaning, grinding, drying, or freezing mainly to preserve the food, make it safe to eat, or prepare it for cooking, without altering its nutritional content significantly.
For example: fresh produce, grains, meat, eggs, milk, and nuts, as well as frozen and fruits
Group 2: Processed Culinary Ingredients
They are derived from Group 1 foods through processes that involve pressing, refining, grinding, or milling. These ingredients are used to cook and season Group 1 foods and are not usually consumed on their own. The processing here is intended to produce culinary ingredients that enhance the flavor, texture, and appearance of food when cooking or preparing meals.
For example: oils, butter, sugar, salt, flour, and vinegar
Group 3: Processed Foods
A combination of Group 1 and Group 2 foods that typically undergo preservation processes like canning, bottling, or curing, and often contain added salt, sugar, or oils. The primary goal is to enhance the shelf life, safety, and palatability of foods, with some changes in their nutritional profiles due to the addition of preservatives and other ingredients.
For example: canned vegetables, cheese, freshly baked bread, smoked meats, and pickled foods
Group 4: Ultra-Processed Foods
UPFs are industrial formulations. They are typically made entirely or mostly from substances extracted from foods (e.g., oils, fats, sugars, starches, proteins), derived from food constituents (e.g., hydrogenated fats, modified starch), or synthesized in laboratories (e.g., flavor enhancers, color additives). These foods often contain little to no whole foods and are designed to be convenient, affordable, and highly palatable. This processing aims to create products that are ready-to-eat, attractive, and convenient, with a focus on maximizing shelf-life, taste, and profit margins.[12] This group is the most distant from natural foods.
For example: soft drinks, packaged snacks, instant noodles, mass-produced breads, ready-to-eat meals, and many breakfast cereals
The Food and Beverage Classification System (SIGA)
The Siga classification was developed by a French start-up of the same name in 2020. It is based on the NOVA groups but further considers, (i) the impact of processing on the food/ingredient matrix; (ii) the contents of added salt, sugar and fat; (iii) the nature and number of markers of ultra-processing (MUPs); and (iv) the levels of at-risk additives.[13] The algorithm ultimately divides foods into nine different categories. Categories are given a rating that is meant to encourage product reformulation, packaging design, SEO, and supermarket management.[14]
International Agency for research on Cancer (IARC) Classification
IARC developed a relatively simple three-tiered food processing classification system specifically for a prospective study investigating the relationship between nutrition and cancer in Europe.[15] The tiers include (1) non-processed foods, (2) moderately processed foods, such as packaged salad, frozen food ingredients, extra virgin olive oil, fruits and vegetables canned in water/brine. (3) highly processed foods, which are those that have been industrially prepared and require little work at home beyond heating in some way.
The International Food Information Council (IFIC) Classification
The IFIC system categorizes foods based on the type and purpose of processing rather than the degree of processing. It aims to explain how processing affects food safety, quality, and nutritional content.[16] Importantly, IFIC is a non-profit organization funded and staffed primarily through ties to the processed food industry in the US.
IFIC differentiates between: (1) Minimally processed foods: Foods that have been slightly altered for preservation or convenience, like washed and packaged fruits. (2) Foods processed for preservation: Foods with added preservatives or those that have undergone canning or freezing. (3) Mixtures of combined ingredients: Foods made by combining ingredients like oils, sugars, and starches, such as sauces or salad dressings. (4) Ready-to-eat foods: Foods that require no preparation, like snacks. (5) Prepared foods/meals: ready-made meals like frozen dinners.
Others
Further food classification systems have been developed by researchers at the University of North Carolina[17], the International Food Policy Research Institute (IFPRI)[18], the National Institute of Public Health of Mexico[19], and others.
Food contact materials & ultra-processed foods
Plastics are a versatile group of materials that currently play a significant role throughout the food system, especially UPFs, from cultivation to consumption.[22] In food cultivation, plastic mulch films and film-covered greenhouses are often used to protect crops, promote growth, and prevent damage from pests and weather. During transportation, plastic storage containers provide a lightweight and durable means of moving food from farms to processing facilities. In factories, plastics are especially prevalent in the processing of ingredients into foodstuffs. Finally, consumer-facing packaging of UPFs is made of plastics largely due to its functionality and cost-effectiveness.
However, this reliance on plastics comes with costs. The cheapness of plastics is largely due to externalized costs – physical and chemical pollution is not built into the price (FPF reported also here).
The focus on long shelf lives, global distribution, high-throughput production, and use as a marketing tool to stand out on crowded supermarket shelves, has driven the food industry’s reliance on plastics. Yet, this emphasis on convenience comes with potential risks from synthetic chemical exposure.
Chemical migration
FCMs can be generally divided into two groups, inert and non-inert. For largely non-reactive (inert) materials such as stainless steel, fired ceramic, and glass, only chemicals from the surface that are directly in contact with the food can migrate. An example would be detergents that are not completely rinsed during dishwashing, or an added coating. However, chemicals within the material or from the outside, such as printing inks or adhesives, cannot move through the material and reach the food itself. This high inertness and other barrier properties are due to the rigid chemical structure of the material which makes it highly resistant to degradation.
Paper, board, and plastics are non-inert materials. Their material structures make it easier for any smaller, unbound chemicals present, such as plasticizers, colorants, inks and adhesives, to migrate from within the material or from the material’s exterior into the food. Printing ink, for example, has been shown to migrate through paper and board packaging into dry foods (FPF reported).
Containers made of inert materials release less amounts of chemicals into food when they are used under the same conditions.
Chemical migration from any FCAs, whether processing equipment or packaging, increases over time (for example, during storage), at higher temperatures (for example, when foods are heated prior to filling into packaging), with fatty or acidic foods (for example, dairy products or carbonated sweet beverages), and when packaged in smaller serving sizes (for example, single servings of salad dressings) (FPF reported). All four of these factors are common elements of UPFs.
Exposure to FCCs of Concern
At least 3601 FCCs have been measured in humans and for at least 1700 there is evidence for their migration from FCAs. Some FCCs are known to be chemicals of concern, linked to breast cancer and other types of chronic diseases (FPF reported).
A 2024 study undertaken in the US reported a relationship between consumption of ultra-processed food during pregnancy and phthalate exposure.[20] Further, the authors found that “lower household income and lower maternal education levels were associated with higher” urinary metabolite levels of the phthalate DEHP, due to higher ultra-processed food intake. They implicate socioeconomic barriers as a further burden to accessing foods free of these exposures which can prevent consumers from following dietary recommendations aimed at reducing phthalate exposure. As a consequence, the authors call for policies to mandate changes in food packaging and processing equipment, to reduce phthalate exposure for the entire population (FPF reported).
Exposure to Micro- and Nanoplastics
Similarly, FCMs can also be a source of micro- and nanoplastics. A 2024 study reported that highly-processed protein products purchased in the US contained significantly more microplastics than minimally-processed products. A hypothesis is that plastic processing equipment is one main source of these particles that can migrate into foodstuffs during normal and intended use.[21]
The Role of Food Processing Equipment
The production of ultra-processed foods relies heavily on sophisticated food processing equipment, which plays a crucial role in transforming raw ingredients into the final, hyperpalatable product. This equipment not only enables the mass production of food but also helps in achieving the desired texture, flavor, and appearance that make UPFs hyperpalatable.
To achieve these results, the foodstuffs are often processed under intense pressure and high temperatures which increases chemical migration (FPF reported).
Health Implications
The reliance on such advanced processing equipment, while beneficial for producing large quantities of convenient food, often comes at the cost of nutritional quality and increased burden of synthetic substances.[22][23] The end products are engineered for maximum taste and convenience but with a hidden cost that it may contribute to various non-communicable diseases, such as obesity, diabetes, and cardiovascular diseases, due to their high content of unhealthy fats, sugars, and sodium, along with the presence of additives and the low content of essential nutrients.
An umbrella review of 75 studies found consistent associations “between UPF consumption and dozens of adverse health outcomes including premature all-cause mortality, cancer, and mental, respiratory, cardiovascular, gastrointestinal, and metabolic ill health.”[24]
A French epidemiological study of nearly 105,000 participants whose diets were rated using the NOVA classification found “a 10% increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of greater than 10% in risks of overall and breast cancer.”[25] The authors discuss several hypotheses for this increase in cancer including exposure to FCCs like acrylamide (CAS 79-06-1) and bisphenol A (BPA, CAS 80-05-7). They describe how “food processing and particularly heat treatments produce neoformed contaminants (for example, acrylamide) in ultra-processed products such as fried potatoes, biscuits, bread, or coffee.” Nearly 200 FCCs with characteristics linked to breast carcinogenesis have been detected in FCMs.[26]
A study of pregnant women in the US showed that the women’s’ diets were composed of 9.8 – 59% of ultra-processed foods, according to the NOVA classification system. The scientists reported that “each 10 % higher dietary proportion of ultra-processed foods was associated with 13.1 %” higher urinary levels of the molar sum of five di(2-ethylhexyl) phthalate (CAS 117-81-7) metabolites (ΣDEHP) (FPF reported).
Takeaways
- Ultra-processed foods (UPFs) and plastics are deeply intertwined, contributing to significant health and environmental issues.
- UPFs’ reliance on plastic packaging is driven by cost-effectiveness and convenience, but also results in exposure to food contact chemicals (FCCs).
- The FCCs in ultra-processed foods have been linked to adverse health outcomes independently of the other concerns around UPFs
References
[1] Juul, F., Parekh, N., Martinex-Steele, E., Monteiro, C.A., Chang, VW. “Ultra-processed food consumption among US adults from 2001 to 2018.” The American Journal of Clinical Nutrition. DOI: 10.1093/ajcn/nqab305
[2] Geueke, B., Groh, K. J., Maffini, M. V., Martin, O. V., Boucher, J. M., Chiang, Y. T., et al. (2022). Systematic evidence on migrating and extractable food contact chemicals: Most chemicals detected in food contact materials are not listed for use. Critical Reviews in Food Science and Nutrition DOI: 10.1080/10408398.2022.2067828
[3] Gibney, Michael J. (February 2019). “Ultra-Processed Foods: Definitions and Policy Issues.” Current Developments in Nutrition. DOI: 10.1093/cdn/nzy077
[4] Taissa Pereira de Araújo, Milena Miranda de Moraes, Cláudia Afonso, Cristina Santos, and Sara S. P. Rodrigues. (February 2022). “Food Processing: Comparison of Different Food Classification Systems.” Nutrients. DOI: 10.3390/nu14040729
[5] Monteiro CA, Levy RB, Claro RM, Castro IR, Cannon G. (2010). “A new classification of foods based on the extent and purpose of their processing.” Cad Saude Publica. doi: 10.1590/s0102-311×2010001100005.
[6] Popkin, BM; Milesc, DR; Tailliea, LS; Dunford, EK. (2024). “A policy approach to identifying food and beverage products that are ultra-processed and high in added salt, sugar and saturated fat in the United States: a cross-sectional analysis of packaged foods.” The Lancet. DOI: 10.1016/j.lana.2024.100713
[7] Fiolet T, Srour B, Sellem L, Kesse-Guyot E, Allès B, Méjean C, Deschasaux M, Fassier P, Latino-Martel P, Beslay M, Hercberg S, Lavalette C, Monteiro CA, Julia C, Touvier M. Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort. BMJ. 2018 Feb 14;360:k322. doi: 10.1136/bmj.k322. PMID: 29444771; PMCID: PMC5811844.
[8] Romero Ferreiro C, Lora Pablos D, Gómez de la Cámara A. Two Dimensions of Nutritional Value: Nutri-Score and NOVA. Nutrients. 2021 Aug 13;13(8):2783. doi: 10.3390/nu13082783. PMID: 34444941; PMCID: PMC8399905.
[9] Juul F, Martinez-Steele E, Parekh N, Monteiro CA, Chang VW. Ultra-processed food consumption and excess weight among US adults. Br J Nutr. 2018 Jul;120(1):90-100. doi: 10.1017/S0007114518001046. Epub 2018 May 6. PMID: 29729673.
[10] Marino M, Puppo F, Del Bo’ C, Vinelli V, Riso P, Porrini M, Martini D. A Systematic Review of Worldwide Consumption of Ultra-Processed Foods: Findings and Criticisms. Nutrients. 2021 Aug 13;13(8):2778. doi: 10.3390/nu13082778. PMID: 34444936; PMCID: PMC8398521.
[11] Monteiro, C.A., Cannon, G., Lawrence, M., Costa Louzada, M.L. and Pereira Machado, P. (2019). Ultra-processed foods, diet quality, and health using the NOVA classification system. Food and Agriculture Organization. DOI:
[12] Wood, Benjamin; Ella Robinson, Phillip Baker, Guillermo Paraje, Mélissa Mialon, Christoffer van Tulleken, & Gary Sacks. (November 2023). “What is the purpose of ultra-processed food? An exploratory analysis of the financialisation of ultra-processed food corporations and implications for public health.” Globalization and Health. (pdf).
[13] Davidou S , Christodoulou A , Fardet A , Frank K. (2020). “The holistico-reductionist Siga classification according to the degree of food processing: an evaluation of ultra-processed foods in French supermarkets.” Food Funct. doi: 10.1039/c9fo02271f.
[14] Flora Southey (August 12, 2019). “French food label exposes ultra-processed products: ‘Food is more than a sum of its nutrients’.” Food Navigator.
[15] Slimani N, Deharveng G, Southgate DA, Biessy C, Chajès V, van Bakel MM, Boutron-Ruault MC, McTaggart A, et al. (November 2009). “Contribution of highly industrially processed foods to the nutrient intakes and patterns of middle-aged populations in the European Prospective Investigation into Cancer and Nutrition study.” Eur J Clin Nutr. DOI: 10.1038/ejcn.2009.82
[16] Eicher-Miller H.A., Fulgoni V.L., Keast D.R. (2012). “Contributions of Processed Foods to Dietary Intake in the US from 2003–2008: A Report of the Food and Nutrition Science Solutions Joint Task Force of the Academy of Nutrition and Dietetics, American Society for Nutrition, Institute of Food Technologists, and International Food Information Council.” J. Nutr. DOI: 10.3945/jn.112.164442
[17] Poti JM, Mendez MA, Ng SW, Popkin BM. (2015). “Is the degree of food processing and convenience linked with the nutritional quality of foods purchased by US households?” Am J Clin Nutr. DOI: 10.3945/ajcn.114.100925.
[18] Asfaw, Abay. (2011). “Does consumption of processed foods explain disparities in the body weight of individuals? The case of Guatemala.” Health Economics. DOI: 10.1002/hec.1579
[19] González-Castell D, González-Cossío T, Barquera S, Rivera JA. (2007). “Alimentos industrializados en la dieta de los preescolares mexicanos.” [Contribution of processed foods to the energy, macronutrient and fiber intakes of Mexican children aged 1 to 4 years]. Salud Publica Mex. DOI: 10.1590/s0036-36342007000500005 (in Spanish)
[20] Baker, B. H. et al. (2024). “Ultra-processed and fast food consumption, exposure to phthalates during pregnancy, and socioeconomic disparities in phthalate exposures.” Environment International. DOI: 10.1016/j.envint.2024.108427
[21] Milne, H. M. et al. (2023). “Exposure of U.S. adults to microplastics from commonly-consumed proteins.” Environmental Pollution. DOI: 10.1016/j.envpol.2023.123233
[22] Yates, J; et al. (2024). “A toxic relationship: ultra-processed foods & plastics.” Globalization and Health. DOI: 10.1186/s12992-024-01078-0
[23] Buckley, JP; et al. (2019). “Ultra-processed food consumption and exposure to phthalates and bisphenols in the US National Health and Nutrition Examination Survey, 2013–2014.” Environment International. DOI: 10.1016/j.envint.2019.105057
[24] Dai, S; et al. (2024). “Ultra-processed foods and human health: An umbrella review and updated meta-analyses of observational evidence.” Clinical Nutrition.
[25] Fiolet T, Srour B, Sellem L, Kesse-Guyot E, Alles B, Mejean C, et al. (2018). “Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort.” BMJ DOI: 10.1136/bmj.k322
[26] Parkinson, LV; Geueke, B; Muncke, J. (2024). “Potential mammary carcinogens in food contact articles: Implications for policy, enforcement, and prevention.” Frontiers in Toxicology. DOI: 10.3389/ftox.2024.1440331
