Research Project: Approaches to Dietary and Physical Activity Guidelines Adherence

Location: Healthy Body Weight Research

2025 Annual Report

Objectives
Objective 1: Evaluate diets composed primarily of ultra-processed or less processed foods that meet dietary guidelines recommendations on chronic disease risk factors. [NP107, C3, PS3A; C4, PS4B] Sub-objective 1.A: Develop study menus that align with DGA recommendations and have most of their energy coming from foods with different degrees of processing (e.g., one menu will have >80% kcal from UPFs and the other menu will have >80% kcal from less processed foods). Sub-objective 1.B: Determine whether a DGA diet comprised of primarily UPFs will impact the following markers of chronic disease compared to a DGA diet comprised of less processed foods: • blood pressure • fasting glucose and insulin concentrations • lipid panel (total, HDL-C, LDL-C, triglycerides) Objective 2: Determine the relationships among dietary intake, physical activity, and behavior motivation. [NP107, C3, PS3A; C4, PS4B] Sub-objective 2.A: Determine whether daily consumption of ultra-processed fruits increases RRV (produces incentive sensitization) of low-processed fruits or ultra-processed fruits. Objective 3: Determine consumption patterns of ultra-processed foods, consumer perception and understanding of food processing, and influences of processing on consumer decisions. [NP107, C1, PS1B; C3, PS3A and PS3B] Sub-objective 3.A: Conduct a survey study across a nationally representative cross-section of the U.S. adult population to assess attitudes towards, understanding of, and consumption of UPF (as defined by NOVA).

Approach
The Dietary Guidelines for Americans (DGA) are based on scientific evidence and are intended to promote health and prevent nutrition-related diseases. However, most Americans do not meet DGA recommendations in part because doing so requires long-term adherence to behavior change. Behavioral choice theory posits that engaging in a behavior is dependent on barriers to engage in the behavior relative to the reinforcing value of the behavior. If a healthy behavior requires much work and has a low reinforcing value, people will not engage in it. One topic for consideration in the 2025-2030 DGA is the impact of “degrees” of food processing on health outcomes. “Ultra-processed” foods (UPF) provide convenience and reduce barriers to consumption. While cross-sectional research posits that UPF are detrimental to health, many UPF are nutrient-dense. Uncertainty among the research community regarding definitions of UPF is well-documented; however, consumer definitions of, perceptions of, and attitudes towards UPF have not been extensively evaluated. Nutrient-dense UPF could promote health to the same extent as less-processed foods and reduce barriers for healthy food consumption. Repeated consumption of nutrient-dense UPF may increase the reinforcing value of nutrient-dense UPF and other nutrient-dense foods, regardless of their level of processing, resulting in greater diet quality and reduced chronic disease risk. To date, there is little empirical data on the effects of food processing on either behavioral choice or chronic disease markers. We propose that, when matched for diet quality, micronutrient content, and food type, a more- versus less-processed healthy eating pattern will not differ in impact on biochemical indicators of chronic disease. The results of this project will help inform dietary guidance, thereby helping clinicians, public health professionals, and policymakers to improve the health of Americans.

Progress Report
The first year of the project plan, titled the “Approaches to Dietary and Physical Activity Guidelines Adherence,” started in FY25. Objective 1: Researchers at Grand Forks, North Dakota made progress towards Objectives 1A and 1B. Objective 1A includes developing and refining menus for an intervention study (the Diet, Activity, and Behavior Study, or “DAB”) that compares the impact of consuming a Dietary Guidelines for American (DGA) eating pattern with most energy coming from ultra-processed foods to a DGA pattern with most energy coming from unprocessed foods on health outcomes, including blood pressure and other markers of cardiovascular health. Draft menus are developed and are currently being refined for taste and product availability. Final menus will be uploaded to a data repository when complete. Objective 1B was to develop and refine the protocol for said human intervention study and obtain Institutional Review Board (IRB) approval for human study. The study protocol has been developed and refined but remains under review with IRB. It is scheduled to be reviewed by the full IRB board on July 11, 2025. ARS scientists in Grand Forks, North Dakota, investigated how social modeling of eating behaviors, that is, how others eat and drink, impacts selection of a nutrient-dense compared to a nutrient-poor beverage option. This study focuses on understanding the role of social modeling on drinking milk, a food within the underconsumed dairy food group, which provides essential nutrients in the American diet. This study was terminated after 100 participants had completed the study. This study will fill a critical need for scientific evidence on the role that observing the eating and drinking habits of others affects the decision to consume a nutrient-dense food or beverage. ARS scientists in Grand Forks, North Dakota, are examining correlates and predictors of young adults’ eating habits, with particular emphasis on sociodemographics, reproductive health, and food upbringing. Emerging adulthood is a critical period of increasing autonomy during which key health behaviors are established; life course research finds food habits in early adulthood set individuals on lifelong nutrition trajectories, influencing food habits, preferences, and health outcomes for decades. This study was completed in November 2024 with data from approximately n=1123 young adults. Results of this study will provide essential information on young adults’ eating habits to assist in improving disparities in physical health in later adulthood. ARS scientists in Grand Forks, North Dakota, are investigating whether consuming an Indigenous diet produces non-targeted increases in physical activity and health of adult Great Plains Indians. Discussions with leadership of United Tribes Technical College (UTTC, Bismark, North Dakota) led to a collaboration and agreement between the USDA-ARS Grand Forks Human Nutrition Research Center (GFHNRC) and faculty from UTTC and Sitting Bull College (Fort Yates, North Dakota) to conduct the research. Working with UTTC, ARS scientists developed a healthy intervention diet comprised of Indigenous foods and recipes that were part of traditional food systems of the Great Northern Plains prior to establishment of reservations by the Indian Appropriations Act of 1851. This study was terminated after 7 participants (out of 15 needed) completed the study. Results of this study will provide critical insights into potential benefits of healthy and traditional foods for local Indigenous communities in North Dakota. ARS scientists in Grand Forks, North Dakota, are investigating the impact of using more- or less-processed foods in equally healthy menus on the time required to prepare those menus, their cost, and their relative shelf stability. Researchers found that diets comprised of less-processed foods required more time to prepare, cost more money, and had less overall shelf stability when compared to similar diets comprised of primarily more-processed foods. This study provides critical insights into the impacts of processed foods on lifestyle factors, affordability, conservation, and convenience.

Accomplishments
1. Diets comparable in overall quality, food type, and vitamin/mineral content can be comprised of mostly ultra-processed or mostly unprocessed foods and beverages. There is a great deal of interest in and concern about the potential adverse cardiometabolic health impacts of ultra-processed food (UPF) consumption in the nutrition science literature and among consumers. The randomized controlled trials that have been conducted on this topic to date did not control for diet quality, food type, or micronutrient content. Researchers in Grand Forks, North Dakota, demonstrated that menus could be comprised of mostly UPFs and mostly unprocessed foods with comparable diet quality, food types, and micronutrient content.

2. Development of a novel methodology to evaluate preparation time for menus with more- versus less-processed foods. None of the research published to date quantifies the amount of time required to prepare comparable menus comprised of mostly ultra-processed foods compared to menus comprised of mostly less-processed foods. Researchers in Grand Forks, North Dakota, evaluated the impacts of processing on preparation time, finding that diets comprised of mostly less-processed foods required more time to prepare while providing similar nutrition and quality as diets comprised of mostly ultra-processed foods. This work provides robust evidence to help inform nutrition policy, healthcare practitioners, and consumers on practical considerations of healthy diets, namely, the time required to prepare meals.

3. Development of a novel methodology to evaluate shelf stability of overall diets. Improved shelf-stability is often presented in the literature as an asset of processing food. However, shelf-stability of overall dietary patterns has not been quantified or compared. ARS scientists in Grand Forks, North Dakota developed a method to assess shelf stability and used it to compare similar menus containing more- or less-processed foods. This research was the first effort to develop a method of quantifying and comparing shelf stability of different dietary patterns at a consumer level. Processed foods such as canned and dried fruits may improve consumer access to nutrient-dense foods by having a longer shelf-life and, therefore, being less likely to spoil relative to less-processed foods like fresh fruits. Shelf stability is especially relevant to food access in the U.S., as most consumers live more than 2 miles from the nearest supermarket. This research posits a methodology utilizable by the nutrition research community to evaluate shelf stability alongside other metrics of food access, which can be used to develop both healthy and accessible dietary patterns.

4. Evaluated diet quality among emerging adult population (18-23 years of age) using epidemiological data. The past two iterations of the Dietary Guidelines Scientific Advisory Committee Report (2020-2025 and 2025-2030) indicate that emerging adults may have the lowest diet quality among the U.S. population. Yet, diet quality data about this group specifically has not been extracted from epidemiological data. In partnership with academics, ARS researchers in Grand Forks, North Dakota, investigated diet quality as well as demographic, socioeconomic, and health-related characteristics among young adults from 2015-2018. Diet quality was significantly lower among this emerging adult population compared to the general adult population. This research indicates a specific need for tailored public health interventions to improve diet quality among this sector of the population.

Review Publications
Promschmidt, C., Villano, D., Hess, J.M. 2025. Perspectives on ultra-processed food research: critical questions and next steps. Nutrition Today. 60(2):53-58. https://dx.doi.org/10.1097/NT.0000000000000740.
Brishti, A., Johnson, S., Palmer, D.G., Raihan, M., Yan, L., Casperson, S.L. 2025. Effects of defined voluntary running distances coupled with high-fat diet consumption on the murine skeletal muscle transcriptome. Physiological Reports. 13(2). Article e70170. https://doi.org/10.14814/phy2.70170.
Smith, J.L., Comeau, M.E., Hess, J.M. 2025. Social, behavioral, and psychological predictors of young women’s food choices: a scoping review. Nutrients. 17(6). Article 932. https://doi.org/10.3390/nu17060932.
Hess, J.M., Comeau, M.E., Scheett, A., Bodensteiner, A., Levine, A.S. 2025. Using less processed food to mimic a standard American diet (sad) does not improve nutrient value and may result in a shorter shelf life at a higher financial cost. Current Developments in Nutrition. 8(11). Article 104471. https://doi.org/10.1016/j.cdnut.2024.104471.
Cowan-Pyle, A.E., Bailey, R.L., Gao, J., Hess, J.M., Ademu, L.O., Lankes Smith, J., Mitchell, D.C., Racine, E.F. 2025. Dietary quality and diet-related factors among u.s. emerging adults (18-23y) are a cause for concern, nhanes 2015-2018. Journal of Nutrition. 154(8):2524-2533. https://doi.org/10.1016/j.tjnut.2024.06.015.
Hess, J.M., Comeau, M.E., Palmer, D.G. 2025. Preparation time does not reflect nutrition and varies based on level of processing. Journal of Nutrition. 155(7):2416-2422. https://doi.org/10.1016/j.tjnut.2025.05.020.