“When equality is given to unequal things, the resultant will be unequal.”
— Plato, Laws, Books 1-6
Ultraprocessed foods (UPFs) are commonly perceived and often presented as the latest incarnation of the natural evolution of food. Hundreds of thousands of years ago, our ancestors hunted and gathered food that was, for the most part, consumed immediately. There is evidence dating back at least 14,000 years ago that humans began preserving food by dehydrating fruits, vegetables, and meat in the sun. Adding salt to preserve food was another early intervention. This likely led to fermentation and pickling, which can be traced back over 7000 years, with archaeological findings in Iran suggesting the presence of fermentation to make wine. And no wine course is complete without a bit of cheese, which dates back to the same time period, although the evidence comes from modern-day Poland. The ancient Incas were known to preserve staples like potatoes through an early natural freeze-drying method that involved leaving the vegetables in the extremely cold and dry air of the mountains. The ancient art of preserving food in honey remains alive and well on the shelves of upscale gourmet boutiques. In all these methods, the integral food matrix remains intact.
Modern interventions, such as canning and refrigeration, appeared in the 19th century. At this time, some of the first ultraprocessed foods, such as margarine and processed cheese food, also emerged, although the classification and labeling of such compounds as “ultraprocessed” would not occur until the 21st century with the introduction of the NOVA classification system in 2009 by Prof. Carlos Monteiro and colleagues from the University of São Paulo in Brazil.
However, it was not until the mid-20th century, following World War II, that UPFs began to increase in prevalence. Cultural changes and technological innovations laid the groundwork for their proliferation, which was promoted and viewed as a natural evolution in food production and preservation. What is often not appreciated in the industrial preparation of UPFs is that the food is manipulated in ways that make it wholly incomparable to the natural products they are often intended to replace.
To create shelf-stable and profitable products, UPFs undergo the destruction of the natural food matrix, which is then reconstructed with the addition of compounds not present in naturally occurring foods. To this is often added additional salt, sugars, and fats that were not part of the original components but increase the consumer’s pleasure response; a property known as hyperpalatability.
This week’s analysis features a recently published study examining how we metabolize ultraprocessed foods.
- The study examined specimens from over 1,000 (1,082) participants in the Interactive Diet and Activity Tracking in AARP (IDATA) Study, who were aged 50-74 years, with 51% female and 49% male.
- Daily UPF (as defined by the NOVA classification) intake was calculated from 24-hour dietary recall questionnaires, with a mean intake of 50% of energy derived from UPFs.
- Data was compared via post hoc analysis with a previous group of volunteers who consumed in-house diets of 0% and 80% UPFs for two-week periods.
- Both serum and urine metabolites were examined.
- There were 90 xenobiotic metabolites within urine and serum samples that correlated with UPF consumption.
- Unique serum and urine metabolites correlated with the level of ultraprocessed food consumption.
The Caveat:
Current conventional wisdom tends to treat ultraprocessed foods on par with their naturally occurring alternatives. The remarkable prevalence of xenobiotics found within human serum and urine samples, correlating with the amount of UPFs consumed, would argue against such an equivalence.
Xenobiotics are a group of chemical compounds that are foreign to an organism’s biological system. The term “xenobiotic” itself means foreign to life, indicating substances not naturally produced or expected to be present within a living being.
Some of these xenobiotics were associated with benzoate metabolism, suggesting an origin related to pollutants, pesticides, drugs, or food additives. Normal benzoate metabolism involves the breakdown of benzoate, a simple aromatic carboxylic acid that is naturally found in some fruits, vegetables, spices, and fermented products. This metabolic pathway is not only present in human cells but also in the gut microbiome, where various bacteria possess the enzymatic machinery to degrade benzoate and structurally related compounds. It is these foreign compounds that suggest that these industrial additives or pollutants affect not only human cells but can also impact the gut microbiome. These findings are in agreement with other data demonstrating the detrimental effects of UPF additives, such as industrial emulsifiers, on the human gut microbiota.
Data such as this suggests a fundamentally different construct between naturally occurring food and ultraprocessed alternatives. A common response to the increase in obesity and type II diabetes (and other chronic disabilities and diseases (CDD)) associated with ultra-processed food consumption is that they are energy-dense and that the problem lies simply in the overconsumption of energy in the form of calories, causing resultant weight gain. The correlation between the increased risk of developing CDD and the consumption of low-calorie, fat-free, or zero-calorie ultraprocessed foods would argue against this hypothesis.
Interim data from an ongoing clinical trial also argue against increased energy density and weight gain as the sole explanation for increased inflammation and CDD associated with increased UPF intake[1]. The study is examining a group of human volunteers consuming four different diets (minimally processed, MP, (no UPF); a classic ultraprocessed diet high in energy density and hyperpalatable foods, UPFhh; an ultraprocessed diet high in energy density but low and hyperpalatable foods, UPFhl; and an ultraprocessed diet low in energy density and low and hyperpalatable foods, UPFll). Whilst the energy intake between the minimally processed diet (MP) and the ultraprocessed food diet low in energy density and hyperpalatable foods (UPFll) was not significant, only the minimally processed food diet was associated with a reduction in body fat. Regardless of caloric intake, all ultraprocessed food diets led to an increase in body fat. If these interim findings are confirmed upon study completion, they provide significant support for the idea that ultraprocessed foods are a fundamentally different form of energy intake compared to what Nature has provided.
Why this matters is that many of the proposed solutions to the UPF problem only call for a reformulation, i.e., remove a particular dye and replace it with an alternative coloring agent. This fails to address potential issues related to the fundamental properties of ultra-processed foods, leading us further astray from meaningful solutions.
[1] (Hall, 2024)
The Study:
Additional Resources:
