Diet that limits ultra-processed foods isn’t automatically healthy, study shows

NEW YORK, June 30 (UPI) -- A diet that limits ultra-processed foods isn't automatically healthy, and the types of foods people eat may matter more than the level of processing used to make them. a new study suggests.

The findings were presented Sunday at the American Society for Nutrition's annual meeting in Chicago.

Researchers compared two menus that reflect a typical Western diet -- one that emphasizes minimally processed foods and the other that focuses on the ultra-processed variety, according to the NOVA Food Classification System.

This system categorizes foods into one of four groups based on processing-related criteria. It was designed by Center for Epidemiological Studies in Health and Nutrition in the School of Public Health at the University of Sao Paulo, Brazil.

The less-processed menu was more than double in price and reached its expiration date more than three times more quickly without providing any additional nutritional value.

This outcome demonstrated that "both ultra-processed and less processed foods can have a low healthy eating score," Allen Levine, a professor emeritus in the Department of Food Science and Nutrition at the University of Minnesota in St. Paul, told UPI via email.

Levine classified the various foods in the NOVA system for the study.

"Also, ultra-processed foods with a healthy eating score similar to the less-processed foods have a longer shelf life and are less costly," Levine said.

Based on these findings, it's possible to consume a low-quality diet even when selecting mostly minimally processed foods, the researchers noted.

"The results of this study indicate that building a nutritious diet involves more than a consideration of food processing as defined by NOVA," the study's principal investigator, Julie Hess, said in a news release.

"The concepts of 'ultra-processed' foods and 'less-processed' foods need to be better characterized by the nutrition research community," said Hess, a research nutritionist at the U.S. Department of Agriculture/Agriculture Research Service Grand Forks Human Nutrition Research Center.

Last year, the team published a study showing that one could assemble a high-quality menu that aligns with dietary guidelines while deriving most of its calories from foods classified as ultra-processed.

For the new study, the researchers posed the opposite question: Can you build a low-quality menu that obtain most of its calories from "simple" foods?

To answer that question, they constructed a less-processed menu, which sourced 20% of calories from ultra-processed foods, and a more-processed menu, which derived 67% of calories from ultra-processed foods. The NOVA system determined the level of processing involved in each menu.

Researchers calculated the menus to have a Healthy Eating Index score of about 43 to 44 out of 100, a relatively low number that reflects poor adherence to the Dietary Guidelines for Americans.

They estimated that the less-processed menu would cost $34.87 daily per person, compared with $13.53 per day for the more-processed menu. They also calculated that the median time to expiration of the less-processed menu items was 35 days compared to 120 days for the more-processed menu items.

The study casts a spotlight on the disconnects between food processing and nutritional value, the researchers said. Some nutrient-dense packaged foods can be classified as ultra-processed -- for instance, unsweetened applesauce, ultrafiltered milk, liquid egg whites, and some brands of raisins and canned tomatoes.

"When it comes to consuming an affordable healthy diet, both nutrition quality and price can be packaged together," said registered dietitian Joan Salge Blake, a clinical professor and director and nutrition programs at Boston University. She was not involved in the study.

Blake recommends using the grocery store circular or app to find healthy foods -- whether fresh, frozen, canned or packaged -- that are on sale and plan your weekly meals around these items.

"Use the Nutrition Facts Panel on the label as a guide to help you decipher the nutritional quality of the foods that you choose rather than being frightened by their level of processing," she said.

However, ultra-processed foods can contribute significantly to obesity and related chronic diseases if they contain high added sugars, unhealthy fats and artificial additives and have low nutritional value, said Dr. Zhaoping Li, a professor of medicine and director of the Center for Human Nutrition at the David Geffen School of Medicine at the University of California-Los Angeles.

"Ultra-processed foods were initially developed to provide convenient and affordable sources of calories aimed at preventing malnutrition," Li said, adding that they have become increasingly popular because they often appeal to consumers' taste preferences with ready-to-eat or ready-to-prepare formats.

She advises replacing ultra-processed foods with various fresh and nutrient-dense foods whenever possible.

A diet composed of whole grains, lean proteins, healthy fats, fruits and vegetables "ensures the body receives the necessary vitamins, minerals and other beneficial compounds," Li said.

"Prioritizing dietary quality can help prevent chronic diseases, improve energy levels and support overall well-being," she added.

The study sends the overall message that there's more to the health value of food than the level of processing it goes through to reach consumers, said Liz Weinandy, a registered dietitian and instructor of practice at The Ohio State University Wexner Medical Center in Columbus.

However, "I don't think anyone will disagree that sugary beverages, candy and snack chips are low in nutritional value and should not be consumed regularly," Weinandy said. "We don't want to put lipstick on a pig."