Why has addressing ultra-processed diets become a top priority?

A significant majority, ranging from 70% to 90%, of the products manufactured by global food corporations are ultra-processed foods (UPFs). Such products are usually extensively packaged, heavily branded, and characterized by a high degree of artificiality. Typically made from low-quality, refined ingredients such as starches, sugars, oils, and/or protein isolates, UPFs require numerous additives like colorants, texturizers, synthetic flavors, and bulking agents to enhance their sensory appeal from initially inferior ingredients to hyperpalatability. As a result, UPFs are concoctions that offer little in terms of nutritional value or satiation and often promote addictive consumption patterns that lead to overeating. By prioritizing convenience, palatability, and profitability, they are designed to dominate the market, displacing traditional foods. Through aggressive marketing and sustainability claims, UPFs drive consumer demand, consolidating corporate power and marginalizing smaller food producers. Socially, they undermine communal eating practices, fostering individualized consumption that can contribute to disconnection and excessive consumption. The widespread influence of UPFs raises significant concerns regarding public health, environmental sustainability, and socio-economic equity within the global food system. Moreover, multinational corporations frequently blur the distinction between UPFs and less processed, benign foods (e.g., yogurt), attempting to create confusion about their health implications. Even if it is true that the classification of UPFs by the NOVA system is not always robust at the level of an individual food item, and that the occasional consumption of UPFs may be unproblematic, the case against UPFs needs to be evaluated at the level of dietary patterns. Western-style diets dominated by UPFs are demonstrably harmful and have been responsible for the rapid deterioration of health whenever and wherever they have been imposed upon traditional cultures in the past.

Annual per capita consumption of ultra-processed foods (UPFs) is estimated at 100 kg in Western Europe and 120 kg in North America and Australasia, with ultra-processed drinks accounting for an additional 180 kg and 120 kg, respectively. In France, two-thirds of conventional industrial foods and half of organic products are categorized as ultra-processed. In high-income countries, UPFs constitute 15-60% of total caloric intake for adults, while in Brazil, it is 13-21%. In the US, over 70% of packaged foods are ultra-processed, and these foods make up 70-80% of the diet for the top consumers in the US, UK, and Australia. Children in Anglosphere countries get 55-65% of their calories from UPFs, with US youth consuming 61-67% of their energy from these foods between 1999 and 2018. Even in France, UPFs account for 46% of children's diets, compared to 35% for adults.

The global situation regarding ultra-processed foods (UPFs) is expected to worsen due to aggressive marketing and the influence of large corporations on policies and science. They are disproportionately consumed by lower socioeconomic groups, exacerbating existing nutritional imbalances and potentially causing metabolic disturbances in their children. Higher socioeconomic groups are also vulnerable, particularly due to marketing around what is promoted as virtuous food choices. Specifically, this relates to the push for plant-based “alternatives” (ultra-processed mock foods) and Nutrient Profiling Systems (NPS, such as Nutriscore). Such strategies tend to downplay the risks of UPFs while overemphasizing the drawbacks of traditional animal source foods. This benefits large food corporations, for instance by reformulating products to meet the algorithms underpinning the NPS. Reformulation typically involves reducing certain nutrients or adding "healthy" ingredients, but this does not necessarily improve the overall healthiness of the food. The negative health impacts of UPFs are not dictated by their nutrient content only, making such reformulations ineffective and sometimes even harmful.

Ultra-processed foods are a primary modifiable target for early prevention of non-communicable diseases, including colorectal cancer, and diets high in UPFs are associated with higher risks of mortality, mental disorders, obesity, and type-2 diabetes. Intervention trials show UPFs consumption cause higher energy intake and weight gain compared to unprocessed diets. A variety of interacting mechanisms has been identified to explain these effects, including the dysregulation of endocrine responses, satiety signals, and immunity and liver functions, as well as adverse impacts on the gut microbiota. All of this is compounded by the nutrient-poor profiles of UPFs, which typically rely on cheap, refined ingredients like starches, sugars, and oils. During processing, the materials used are stripped of fibre and micronutrients, while acellular nutrients are generated due to the degradation of the food matrix. When such free nutrients accumulate beyond what is normally slowly released during digestion, they wreak havoc on the natural responses of both the human body and gut microbiota, which have been fine-tuned during evolution to accommodate wholesome foods. In addition, the combined use of cosmetic additives (colorants, artificial flavours and sweeteners, emulsifiers, etc), the presence of xenobiotics (e.g., from packaging materials), and the generation of harmful chemicals during processing (e.g., acrylamide, oxidation products, advances glycated end products, etc), have raised concerns based on their demonstrated effects on humans and animals, triggering pro-inflammatory signalling in the gut and bodily metabolism.