Ultra-processed food
An ultra-processed food is a grouping of processed food characterized by relatively involved methods of production. There is no simple definition of UPF, but they are generally understood to be an industrial creation derived from natural food or synthesized from other organic compounds. The resulting products are designed to be highly convenient and hyperpalatable, often through food additives such as preservatives, colourings, and flavourings. UPFs have often undergone processes such as moulding/extruding, hydrogenation, or frying.
Ultra-processed foods first became ubiquitous in the 1980s, though the term "ultra-processed food" gained prominence from a 2009 paper by Brazilian researchers as part of the Nova classification system. In the Nova system, UPFs include most bread and other mass-produced baked goods, frozen pizza, instant noodles, flavored yogurt, fruit and milk drinks, diet products, baby food, and most of what is considered junk food. The Nova definition considers ingredients, processing, and how products are marketed; nutritional content is not evaluated. As of 2024, research into the effects of UPFs is rapidly evolving.
Since the 1990s, UPF sales have consistently increased or remained high in most countries. While national data is limited, as of 2023, the United States and the United Kingdom lead the consumption rankings, with 58% and 57% of daily calories, respectively. Consumption varies widely across countries, ranging from 25% to 35%. Chile, France, Mexico, and Spain fall within this range, while Colombia, Italy, and Taiwan have consumption levels of 20% or less.
Epidemiological data suggest that consumption of ultra-processed foods is associated with non-communicable diseases and obesity. A 2024 meta-analysis published in The BMJ identified 32 studies that associated UPF with negative health outcomes, though it also noted a possible heterogeneity among sub-groups of UPF. The specific mechanism of the effects was not clear.
Some authors have criticised the concept of "ultra-processed foods" as poorly defined, and the Nova classification system as too focused on the type rather than the amount of food consumed. Other authors, mostly in the field of nutrition, have been critical of the lack of attributed mechanisms for the health effects, focusing on how the current research evidence does not provide specific explanations for how ultra-processed food affects body systems.
Definitions
Concerns about food processing have existed since at least the Industrial Revolution. The origin of ultra-processed food is more recent: Michael Pollan's influential book The Omnivore's Dilemma referred to highly processed industrial food as 'edible food-like substances'. Carlos Augusto Monteiro cited Pollan as an influence in coining the term 'ultra-processed food' in a 2009 commentary. Some sources have described UPF as "predigested food".Monteiro's team developed the Nova classification for grouping unprocessed and processed foods beginning in 2010, whose definition of ultra-processing became the most widely accepted, refined through successive publications. The identification of ultra-processed foods, as well as the category itself, is a subject of debate among nutrition and public health scientists, and other definitions have been proposed.
A survey of systems for classifying levels of food processing in 2021 identified four 'defining themes':
- Extent of change
- Nature of change
- Place of processing
- Purpose of processing
Monteiro's 2009 commentary
Ultra-processed foods are basically confections of group 2 ingredients , typically combined with sophisticated use of additives, to make them edible, palatable, and habit-forming. They have no real resemblance to group 1 foods , although they may be shaped, labelled and marketed so as to seem wholesome and 'fresh'. Unlike the ingredients included in group 2, ultra-processed foods are typically not consumed with or as part of minimally processed foods, dishes and meals. On the contrary, they are designed to be ready-to-eat or ready-to-heat, and are often consumed alone or in combination.
This definition is as much social as one based on specific ingredients, which makes the understanding of ultra-processed foods highly intuitive, even among untrained consumers. A letter responding to Monteiro's 2009 commentary suggested that the definition 'lacks precision', since it lacks the measurable definitions of traditional food science. Because of this, researchers disagree whether the definition can form a valid basis for scientific investigation. Researchers have developed a quantitative definition for hyperpalatable food, but not for ultra-processed food.
Nova classification
Monteiro's team subsequently presented ultra-processed foods as a group in the Nova food classification system. The system focuses on food processing rather than foods types or nutrients. Nova categorizes foods into four groups: unprocessed or minimally processed foods, processed ingredients, processed foods, and ultra-processed foods.Nova is an open classification that refines its definitions gradually through scientific publications rather than through a central advisory board. The most recent overview of Nova defines ultra-processed food as:
Industrially manufactured food products made up of several ingredients including sugar, oils, fats and salt and food substances of no or rare culinary use. Group 1 foods are absent or represent a small proportion of the ingredients in the formulation. Processes enabling the manufacture of ultra-processed foods include industrial techniques such as extrusion, moulding and pre-frying; application of additives including those whose function is to make the final product palatable or hyperpalatable such as flavours, colourants, non-sugar sweeteners and emulsifiers; and sophisticated packaging, usually with synthetic materials. Processes and ingredients here are designed to create highly profitable, convenient, tasteful alternatives to all other Nova food groups and to freshly prepared dishes and meals.Ultra-processed foods are further defined as measurably distinguishable from processed foods by ingredients "of no culinary use or of additives with cosmetic functions in their list of ingredients."
The Nova definition of ultra-processed food does not comment on the nutritional content of food and is not intended to be used for nutrient profiling.
International Agency for Research on Cancer (IARC)
The International Agency for Research on Cancer, an intergovernmental agency that forms part of the World Health Organization, classifies foods by their degree of processing. This system breaks food into 'non-processed', 'moderately processed', and 'highly processed' food. The system does not take into account the nature or purpose of changes.Siga Index
The Siga Index is a classification system for processed foods developed in France. It is based on the degree of processing and the nutritional quality of foods, using a holistic and reductionist approach.The Siga Index assigns a score from 1 to 100 to each food product, where higher scores indicate higher nutritional quality and lower processing. The Siga Index also defines ultra-processed foods as those with a score below 40, which are considered to have low nutritional value and high levels of additives, preservatives, and artificial ingredients.
International Food Information Council (IFIC)
The International Food Information Council defines five levels of food processing: minimally processed, foods processed for preservation, mixtures of combined ingredients, ready-to-eat processed foods, and prepared foods/meals.NUPENS
The Center for Epidemiological Research in Nutrition and Health at the University of São Paulo has proposed a variant on the Nova classification consisting of: unprocessed, minimally, or moderately processed foods; processed foods; and ultra-processed foods.Economics
The high amount of processing lends ultra-processed food to be subject to different economic constraints compared to natural food.Profitability
Ultra-processed foods often use less expensive ingredients, allowing ultra-processed food to be priced lower. Furthermore, ultra-processed foods are more consistently available in stores. Global production networks of multinational food companies creating ultra-processed food are supported by high brand awareness, aggressive globalization tactics, and the purchasing of local companies selling similar products.Companies selling ultra-processed food frequently target youth consumers and middle income countries. Many of these companies use big data to choose which consumers to market to. Furthermore, the ultra-processed food industry uses indirect and direct lobbying in large countries to influence local food policy.