Study: Even diets composed of less-processed foods can be unhealthy

Key takeaways:

• Diets composed of less-processed and more-processed foods had similar Healthy Eating Index scores.
• The study shows a disconnect between food processing levels and nutritional value.

CHICAGO — A diet made up of less-processed foods had a similar nutritional value as a diet with more-processed foods, but the more-processed diet was less expensive and longer lasting, researchers found.

“Last year, my collaborators and I published a proof-of-concept study in the Journal of Nutrition indicating it was possible to build a diet that both met most recommendations from the 2020 Dietary Guidelines for Americans (DGA) and derived most of its energy from ultraprocessed foods as defined by NOVA categories,” Julie M. Hess, PhD, a research nutritionist at the U.S. Department of Agriculture-Agricultural Research Service Grand Forks Human Nutrition Research Center, told Healio. “This new study continues the work of that publication. In short, if we can build a healthy diet from mostly ultraprocessed foods, could we build a less healthy diet of mostly less-processed foods?”

Several studies have linked ultraprocessed foods, or UPFs, to adverse health outcomes like increased risk for death from all causes, cancer and CVD. However, experts say there is still insufficient evidence to support clinical decisions and policies against their consumption.

In the current study, Hess and colleagues compared the nutritional value, cost and shelf-life of two menus: a less-processed, Western-style menu that derived 20% of its calories from UPFs vs. a more-processed, Western-style menu that derived 67% of its calories from UPFs.

The level of food processing in each menu was based on the NOVA classification system.

Hess and colleagues reported that the less-processed menu and more-processed menu had Healthy Eating Index scores of 44 and 43 out of 100, respectively. Additionally, nutrient densities and the percentage of shelf-stable, frozen and refrigerated foods were similar between the two menus.

The researchers also found that the less-processed menu would cost $34.87 per day per person vs. $13.53 per day per person for the more-processed menu.

Meanwhile, the median time to expiration was 35 days for less-processed menu items compared with 120 days for more-processed menu items.

“The differences in shelf stability and cost between the more- and less- processed American diets were greater than I expected,” Hess said.

According to the release, the study shows a disconnect between food processing levels and nutritional value. For example, some nutrient-dense items classified as ultraprocessed include unsweetened applesauce, milk, raisins and canned tomatoes, Hess noted.

“These studies (the paper published in August 2023 and these new results) are both proof of concept only, indicating the feasibility of developing more- and less-healthy menus (according to DGA criteria) from more- and less-processed foods (according to NOVA criteria),” Hess said. “Human intervention trials would be needed to see how these menus impact health outcomes.”

References:

• Hess, JM, et al. J Nutr. 2023;doi:10.1016/j.tjnut.2023.06.028.
• Hess JM, et al. Unprocessed, but SAD: A standard American diet made with less-processed foods Is still a standard American diet. Presented at: NUTRITION; June 29-July 2, 2024.
• Limiting ultra-processed foods does not necessarily make for a healthy diet. https://www.eurekalert.org/news-releases/1048895. Published June 30, 2024. Accessed June 27, 2024.