Ultraprocessed foods: the be all and end all?
While evidence floods in on the potential damages of ultraprocessed foods, some research efforts highlight the need to maintain perspective.
Ultraprocessed foods have rapidly become the latest bogeyman in the nutritional sciences, sweeping the field and subsequently breaking into the mainstream vernacular with the help of the wildly successful book, Ultra-Processed People, by doctor and molecular virologist Chris van Tulleken (University College London Hospitals, UK).
In the last year alone, studies have been published that expose the potential risk that ultraprocessed foods pose to cardiometabolic health in children, our mental health and kidney function, amongst many more. And, in perhaps one of the most comprehensive studies yet – presented at Nutrition 2024 (29 June–2 July; Chicago, IL, USA) – a team of researchers from the National Cancer Institute (MD, USA) have utilized a 30-year-old dataset of over half a million people to investigate the association between ultraprocessed foods and mortality.
This dataset consisted of 540,000 people between 50 and 71 years old, who completed a detailed questionnaire about their diet and health in the mid-90s. The team classified the level of processing for the multitude of food items noted in the study, breaking them down into food and ingredient types and using expert consultation to align them with the NOVA food classification system. The NOVA classification system divides food into four descending groups: unprocessed or minimally processed foods, processed culinary ingredients, processed foods and ultraprocessed foods.
Overall death rates were compared for those in the top and bottom 10% for ultraprocessed food consumption. The results were adjusted to account for other mortality risk factors such as smoking and obesity. This analysis ultimately revealed that those in the 90th percentile for ultraprocessed food consumption were at a 10% increased risk of all-cause mortality during a median 23-year follow-up than those in the 10th percentile. This was even when accounting for obesity, which was closely associated with ultraprocessed food intake.
Specific foods were also identified as being particularly high risk with study lead Erikka Loftfield commenting that the team, “… observed that highly processed meat and soft drinks were a couple of the subgroups of ultra-processed food most strongly associated with mortality risk and eating a diet low in these foods is already recommended for disease prevention and health promotion.”
While the study puts hard stats to a growing body of evidence indicating the severity of the ultraprocessed foods issue, it did not deliver a causal link for the association. Alongside this inherent risk of ultraprocessed food with other factors accounted for, the link between these foods and obesity should also be considered. The study showed a clear association between BMI and ultraprocessed food, supporting further investigations that propose several mechanisms through which these foods can lead to obesity.
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However, it is important that ultraprocessed foods are considered as one of many factors in a holistic approach to health, rather than eclipsing all the information that has come before, as is often the case with information in the nutritional sciences that makes its way into the mainstream. The urge to remove all ultraprocessed food from one’s diet at the potential detriment of affordably hitting macronutrient requirements could prove to be an issue for some moving forward, which was a case exemplified by another research project presented at Nutrition 2024.
To make this point, a collaborative research effort led by the Grand Forks Human Nutrition Research Center (ND, USA) designed two menus, one with 20% and the other with 67% of its calories from ultraprocessed sources as defined by the NOVA system. Both menus were shown to have a healthy eating index score of 43–44 out of a potential 100, with the low ultraprocessed menu delivering no additional nutritional value, being offered for twice the price and with a shelf life three times shorter than its ultraprocessed counterpart.
This study highlights the disconnect between processing and nutritional value and reinforces the fact that one metric does not overrule the other. Commenting on the impact of the study, senior author Julie Hess stated that “building a nutritious diet involves more than a consideration of food processing as defined by NOVA. The concepts of ‘ultra-processed’ foods and ‘less-processed’ foods need to be better characterized by the nutrition research community.”
While a concerted effort was made to produce these results, and a loose trend can be seen between the increasing health credentials of food the less processed it is, these two studies highlight the key point that, for healthy eating, a range of factors need to be considered.
