New research demonstrates that eating primarily minimally processed foods, as defined by the NOVA classification system, does not automatically result in a healthy diet, suggesting that the type of food we eat may be more important than the level of processing used to make it.
When the researchers compared two menus reflecting the typical Western diet (one emphasizing minimally processed foods and the other emphasizing ultra-processed foods, as classified by the NOVA classification system), they found that the less processed menu was more than twice as expensive and expired more than three times faster, with no added nutritional value.
“This study shows that even if you choose mostly less processed foods, you can still have a poor-quality diet,” said Julie Hess, PhD, a research dietitian at the USDA Agricultural Research Service’s Grand Forks Human Nutrition Research Center, who led the study. “It also shows that while highly and less processed diets can have the same (or less) nutritional value, more processed diets may have a longer shelf life and cost less.”
Dr. Mark Messina, director of nutritional science research at the Soy Nutrition Institute Global, will present the findings at NUTRITION 2024, the American Academy of Nutrition’s flagship annual meeting, taking place June 29-July 2 in Chicago.
The new study builds on one published by the team last year, which demonstrated that it is possible to create a high-quality menu that follows dietary guidelines and gets most of its calories from foods classified as ultra-processed. In the new study, the researchers asked the opposite question: “Is it possible to create a low-quality menu that gets most of its calories from ‘simple’ foods?”
To find out, the researchers created a low-processed menu, with 20% of calories coming from ultra-processed foods, and a high-processed menu, with 67% of calories coming from ultra-processed foods. The level of processing for each menu was determined according to the NOVA classification system.
The Healthy Eating Index for the two menus was calculated to be 43-44 out of 100, a relatively low score indicating low adherence to the Dietary Guidelines for Americans. The researchers estimated that the less processed menu would cost $34.87 per person per day compared to $13.53 per person per day for the more processed menu. They also calculated that the median shelf life of the less processed menu was 35 days compared to 120 days for the more processed menu.
The study looked at the disconnect between food processing and nutritional value, and Hess noted that some highly nutritious packaged foods could be classified as ultra-processed, including unsweetened applesauce, ultrafiltered milk, liquid egg whites, and some brands of raisins and canned tomatoes.
The results of this study show that to create a nutritious diet, it is not enough to consider food processing as defined by NOVA. The concepts of ‘ultra-processed’ and ‘lowly processed’ foods need to be more clearly defined by the nutrition research community.”
Julie Hess, PhD, Research Nutritionist, USDA-ARS Grand Forks Human Nutrition Research Center
Messina The research will be presented at a poster session on Food Choices, Markets, and Policy on Sunday, June 30, from 12:45 to 1:45 p.m. CDT at McCormick Place.Abstract; See below for more details about the presentation.
the purpose: The trend towards “clean eating” with a focus on simple foods suggests that reducing the intake of processed foods is an essential component of a healthy dietary pattern. However, studies have shown that menus containing primarily ultra-processed foods (UPFs) can meet the nutrient and dietary quality recommendations of the Dietary Guidelines for Americans. Whether a diet containing primarily simple foods constitutes a lower quality diet has yet to be investigated. The aim of this study was to compare the dietary quality, shelf life, and cost of two similar Western-style menus: one containing primarily energy from UPFs and the other containing primarily energy from less processed foods, as defined by the Nova food classification system.
Method: First, we developed less processed Western menus (Less Processed Western, LPW; More Processed Western, MPW) with a Healthy Eating Index (HEI) score of approximately 43 to match the HEI score of the previously developed MPW. The level of processing was determined by the Nova classification assigned by an external assessor. The final menus were evaluated for nutritional content and HEI score. The shelf life of the foods was determined using information from the Food Storage Guidance Manual. The status of each food item at the time of purchase (shelf-stable, frozen, refrigerated) was used to estimate the number of days until expiration. The costs of the foods and menus were determined using fall 2023 retail prices from a Midwestern grocery chain.
result: LPW and MPW had similar nutrient density and HEI scores (44 and 43, respectively). LPW contained 20% energy (kcal) from UPF, whereas MPW contained 67% energy from UPF. The relative proportions of shelf-stable, frozen, and refrigerated foods were similar between the two. Using Kaplan-Meier survival analysis, the median shelf life of LPW menu items was 35 days compared to 120 days for MPW menu items. The “per person” cost was $34.87/day for LPW and $13.53/day for MPW.
Conclusion: Both the less and more processed menus offered lower quality meals, but the LPW was more than twice as expensive as the MPW and had a shorter overall shelf life. Processing is not a proxy for diet quality, and less processed foods may be more expensive and have a shorter shelf life.
Funding source: USDA Agricultural Research Service Project Grant #3062-51000-057-00D
sauce:
American Academy of Nutrition
Article correction
- July 3, 2024 – This story has been temporarily removed pending review. The study summary and press release attempt to debunk the idea that less processed foods are inherently healthier, but they overlook several important aspects. First, equating cost and shelf life with diet quality is misleading, as health benefits often come at a price. Second, the low Healthy Eating Index scores for both menus suggest the study was poorly designed, as a truly balanced diet would score higher regardless of degree of processing. Finally, focusing solely on the NOVA classification without considering food quality and nutrient density provides an incomplete picture of dietary healthiness. We will update this story accordingly once the full paper is available.
- July 2, 2024 – We have changed the title from “Study shows eating mostly minimally processed foods does not translate to a healthy diet” to more clearly communicate that this content is a press release of results presented at NUTRITION 2024 and not a peer-reviewed journal study.
