The Hidden Threat of Ultraprocessed Foods


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Ultraprocessed foods (UPFs) have become a significant concern in modern nutrition due to their potential adverse health effects. These foods, which include items like sugar-sweetened beverages, highly processed meat products, flavored yogurts, packaged snacks, and breakfast cereals, are more durable and cheaper than less processed options but are often nutrient-deficient and high in calories, sugar, fat, salt, and a host of additives. Emerging evidence links higher consumption of UPFs as an important risk factor in the evolving worldwide epidemic of various noncommunicable diseases and related mortality, in particular the rise in younger and younger populations.

“…evidence links higher consumption of UPFs as an important risk factor in the evolving worldwide epidemic of various noncommunicable diseases…”

The concept of UPFs was first introduced in 2009 by Brazilian nutritionist Carlos Monteiro, who developed the NOVA classification system. This system categorizes foods into four groups:

  • Unprocessed or minimally processed foods
  • Processed culinary ingredients
  • Processed foods
  • UPFs

Processed foods undergo minimal alterations, such as the addition of salt, sugar, oil or fermentation, while UPFs are highly modified products created through industrial processing methods that go far beyond traditional culinary practices. Most importantly, they often contain ingredients not typically used in home cooking, such as hydrolyzed proteins, maltodextrin, high fructose corn syrup and artificial additives. Examples include sugary drinks, packaged snacks, reconstituted meat products, and ready-to-eat meals. The hallmark of UPFs is their high content of added sugars, unhealthy fats, and salt, combined with low nutritional value.

“…not all UPFs play a role in the current obesity epidemic.”

It is important to remember that not all UPFs play a role in the current obesity epidemic. An important factor is the amount and regularity that one consumes these foods. Let’s look at the simple example of an apple. The apple you pick from a tree, without peeling it or removing its core and seeds, represents the unprocessed version of this healthy food item. Removing skin and seeds from genetically engineered super sweet apples still makes it a minimally processed food, even though some of the most health promoting components, the polyphenols which are concentrated in the peel and in seeds have been genetically or mechanically removed. Cooking the apple and turning it into apple sauce without addition of extra sugar or chemicals would turn the apple into a processed food, while slicing the apple, adding lots of sugar and making it part of an apple pie, and adding chemicals to the apple pie to increase its shelf life, creates an UPF version of the apple with few if any remaining health benefits. But if you eat your homemade piece of apple pie once or twice a year at a birthday party, it will hardly add to your disease risk.

“…enjoying a tiny piece of high quality praline every once in a while will hardly have any negative effects on your health.”

Having grown up in a traditional family business making delicious chocolates and cakes, I have to admit that most of the products coming out of my parents’ business could be categorized as UPFs, in particular the chocolates created to maximize their hedonic quality without any consideration of potential health consequences. While the chocolate production starts with the cocoa beans packed with health promoting flavonol polyphenols, several processing steps completely remove this “medicine of nature” while at the same time adding saturated fats and sugar to create the final product. But enjoying a tiny piece of high quality praline every once in a while will hardly have any negative effects on your health.

The prevalence of UPFs has surged over the past few decades, driven by urbanization, economic development, and changes in lifestyle. Their convenience and long shelf life make them appealing in fast-paced societies where time for meal preparation is limited. Supermarkets are stocked with a plethora of these products, highly visible, often marketed aggressively and positioned as convenient solutions for busy individuals. A growing number of plant-based meats like the Impossible Burger have recently joined the UPF category, launching a discussion about their proclaimed health benefits. Until conclusive scientific evidence is available to demonstrate their health promoting effects, there is reason for skepticism of products made from more than 15 ingredients.

“The creation of UPFs is primarily motivated by economic considerations within the food industry.”

The processes and ingredients used for UPFA are specifically designed to maximize profitability by incorporating low-cost ingredients, ensuring long shelf-life, and emphasizing branding. Furthermore, ultra-processed foods are engineered to be convenient and hyperpalatable, making them a potential replacement for other food groups within the Nova classification, particularly unprocessed or minimally processed foods.

A major factor in the increasing popularity of UPFs is their addictive nature, maximized intentionally by the modern food industry. The combination of sugar, fat, and salt in these products is known to trigger reward pathways in the brain (in particular the dopamine system), leading to overeating, food cravings and ultimately food addiction. It is no coincidence that many “addiction experts” from the tobacco industry have migrated into companies designing the most addictive foods. This engineered addictive quality undermines self-control and perpetuates unhealthy eating patterns.

The components in UPFs that contribute to gastrointestinal diseases and to poor gut health are still being studied. However, preclinical research indicates that common food additives like sweeteners, coloring agents, emulsifiers, microparticles, or nanoparticles may negatively impact the gut and its microbiome, causing increased intestinal permeability (“leaky gut”), resulting in local and systemic immune activation.

“…the estimated proportion of energy intake from consumption of UPFs has increased among youths in the US, and has consistently comprised the majority of their total energy intake.”

Consumption of UPFs is rising worldwide, with the highest daily energy intake from these foods seen in the United States and the United Kingdom. For example, a large cross-sectional study of US National Health and Nutrition Examination Survey data showed an increase in UPF consumption from 61.4% to 67% of total energy intake among people aged 2-19 years from 1999 to 2018. The study showed that the estimated proportion of energy intake from consumption of UPFs has increased among youths in the US, and has consistently comprised the majority of their total energy intake. Even though correlational, these dietary trends suggest a relationship of the increasing consumption of UPFs among US youths during the past 2 decades, and the rising childhood obesity rate and increased prevalence rates of several chronic diseases, including IBD, and metabolic syndrome.

Several studies have linked UPF consumption with an increased risk of overweight and obesity. For instance, a 2019 trial found that participants on a UPF diet consumed approximately 500 more calories per day and gained around 2 pounds over two weeks compared to those on a minimally processed diet. A 2022 study of nearly 20,000 mother-child pairs found that children of mothers who consumed the most UPFs had a 26% higher risk of overweight/obesity. Moreover, certain UPFs are associated with an increased risk of type 2 diabetes, potentially leading to non-alcoholic (NAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD).

“…high UPF consumption increases the risk for IBD by 47% in adults, particularly for Crohn’s disease…”

There is also a compelling link between UPFs and inflammatory bowel disease. Recent meta-analyses have reported that high UPF consumption increases the risk for IBD by 47% in adults, particularly for Crohn’s disease, but not as strongly for ulcerative colitis. In patients with established IBD, high UPF consumption is associated with more frequent disease flares and active inflammation.

High UPF consumption has also been linked to an increased risk of developing cancer, including colorectal and pancreatic cancers. Conversely, substituting 10% of UPFs with minimally processed foods has been shown to reduce overall cancer risk by 4%.

Healthcare providers can help patients avoid UPFs by discussing the potential health risks and suggesting healthier alternatives, such as the Mediterranean diet, which is rich in fresh fruits and vegetables, monounsaturated fats, complex carbohydrates, and lean proteins. However, such educational interventions need to be implemented early in life when lifelong food prevalences are programmed in the brain. Policy changes, such as taxes on UPFs and mandatory warning labels, have also been proposed to mitigate the impact of these foods on public health. Such labels have been successfully introduced in several countries, including Chile and Argentina, but have run into staunch opposition in the US.

In summary, the health risks, particularly related to GI health, overweight/obesity, diabetes, and cancer, necessitate a critical evaluation of their role in modern diets, most importantly in children. Stricter labeling rules, increased taxation of UPFs and greater educational efforts would go a long away to slow or prevent the growing popularity of expensive anti-obesity drugs.

Emeran Mayer, MD is a Distinguished Research Professor in the Departments of Medicine, Physiology and Psychiatry at the David Geffen School of Medicine at UCLA, the Executive Director of the G. Oppenheimer Center for Neurobiology of Stress and Resilience and the Founding Director of the Goodman-Luskin Microbiome Center at UCLA.