In this chapter, the Committee on Evaluating the Process to Develop the Dietary Guidelines for Americans, 2020–2025 (2020–2025 DGA), reflects on its three tasks in the context of the DGA (in general and specific to the 2020–2025 cycle), summarizes its conclusions from these three tasks, and considers the stated perspectives of the federal agencies relative to the recommendations made by the Committee on Redesigning the Process for Establishing the Dietary Guidelines for Americans (the 2017 report committee). The committee also discusses how actions taken during the 2020–2025 DGA process by the responsible Departments, the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services (HHS), relate to the five values on which the recommended redesign process was based (NASEM, 2017a), which were intended to improve the rigor, integrity, and trustworthiness of the DGA. The chapter concludes with the committee’s overall perspective on its work.
CONTEXT FOR THE COMMITTEE’S CONCLUSIONS RELATIVE TO THE DIETARY GUIDELINES FOR AMERICANS
As discussed in Chapter 2, the DGA are a cornerstone of federal food and nutrition policy and the process to create them is complex. The process is also time-restricted, because federal law dictates that an updated edition of the DGA is to be released every 5 years.1 The DGA process is
1 National Nutrition Monitoring and Related Research Act of 1990, Public Law 101-445, 101st Cong. (October 22, 1990).
complicated to administer because a major portion of the activities undertaken to develop the DGA use only part of the 5-year cycle; many federal agencies contribute to the DGA process; and the lead agency alternates each cycle between USDA and HHS. Creating the DGA is also intellectually complex, as it relies on integrating various types of data to answer inherently complex questions. Dietary intake is both multidimensional and dynamic, with complexities for its measurement and interpretation. Moreover, because much of the available data that examine associations between dietary exposures and health outcomes is from observational studies, versus randomized controlled trials, development of dietary guidelines is challenging. The DGA may, at times, contain controversial recommendations. Such recommendations (or the ensuing debates about those recommendations) may threaten both public and expert perception that the guidelines are trustworthy.
The controversy surrounding the release of the Scientific Report of the 2015 Dietary Guidelines Advisory Committee and the 2015–2020 DGA was described in Chapter 1. In response, the National Academies of Sciences, Engineering, and Medicine (the National Academies) formed the Committee on Redesigning the Process for Establishing the Dietary Guidelines for Americans (the 2017 report committee). In its report, Redesigning the Process for Establishing the Dietary Guidelines for Americans (NASEM, 2017a), the 2017 report committee proposed redesigning the DGA process to address several of its fundamental challenges (NASEM, 2017a).
The process to develop the 2020–2025 DGA was extraordinary for three reasons. First, the 2017 National Academies report was released about 1.5 years after the process had begun. Second, it was the first DGA cycle to include guidelines for infants, toddlers, and pregnant and lactating persons, which required the analysis of additional data and the creation of new dietary patterns for these groups (DGAC, 2020; Dewey et al., 2021). Third, a government shutdown halted activity for about 5 weeks, which delayed the beginning of the DGAC’s work. As a result, it is understandable that the Departments were unable to implement all seven recommendations made by the previous committee.
Implementation of the 2017 National Academies report recommendations ranged in difficulty from relatively easy to more challenging (i.e., those that would require a multi-year process), as acknowledged in the report (NASEM, 2017a). The recommendations also varied in administrative difficulty and cost to implement. In addition, as noted in Chapter 4, some of the recommendations may have had unintended consequences, such as “staff availability, limited transparency, and timeliness of work” as barriers to implementation of the Technical Expert Panels (TEPs).
SUMMARY OF COMMITTEE CONCLUSIONS FOR EACH TASK
As described in Chapter 1, the committee’s Statement of Task included three separate tasks. The committee addressed the first two in its report Evaluating the Process to Develop the Dietary Guidelines for Americans, 2020–2025 A Midcourse Report (NASEM, 2022a), and this report addresses Task 3.
For Task 1, the committee answered the question, “How did the process used to develop the Dietary Guidelines for Americans, 2020–2025 (including scientific methodologies, review protocols, and evaluation processes) compare to the seven recommendations included in the NASEM report entitled, ‘Redesigning the Process for Establishing the Dietary Guidelines for Americans?’” Task 1 was intended to determine the extent to which the recommendations had been implemented; the evidence, findings, and conclusions for Task 1 were presented in the committee’s midcourse report (NASEM, 2022a). Given that Task 3 built on Task 1, this report reflects new information and analyses conducted since the midcourse report was prepared. Therefore, the evidence, findings, and conclusions presented in this report for Task 3 are inclusive of and supersede those for Task 1.
For Task 2, the committee answered the question “Did the criteria used to include scientific studies in the evidence base used to inform the Dietary Guidelines for Americans, 2020–2025, ensure that the evidence base was current (publication date range), rigorous (study design), and generalizable/applicable (health status of study participants) to public health nutrition guidance?” The committee’s evidence, findings, and conclusions relative to Task 2 are presented in its midcourse report (NASEM, 2022a). To address this task, the committee created a set of “committee-identified best practices,” which were used for comparison (NASEM, 2022a). Nutrition Evidence Systematic Review (NESR) could not have known about these practices before its work for the process to develop the 2020–2025 DGA began because the committee created them after NESR’s work was completed. The committee noted that the absence of the ongoing surveillance system recommended in the 2017 National Academies report hampered NESR’s ability to determine the need for and type of updates required to the systematic reviews. After the release of the 2020–2025 DGA, NESR “established a definition and methodology for conducting continuous evidence monitoring” (Appendix D).
The committee concluded that the overall search strategy for developing the systematic reviews was well described and justified and was generally implemented as proposed in the 2017 National Academies report. The committee also concluded that the methodology for developing new systematic reviews was more carefully developed than the methodology for updating existing systematic reviews. The committee concluded that the NESR systematic reviews were appropriately tailored. Tailoring was used to include populations with some chronic health conditions, such as obesity. However, these criteria also excluded individuals with chronic health conditions who participated in studies of secondary prevention. The committee further concluded that the exclusion of prevention-intervention research and research from countries not classified with a high Human Development Index might reduce the generalizability of the outcomes of the systematic reviews to the U.S. population. Finally, the committee concluded that expanding the generalizability of the systematic reviews to cover all Americans remains a challenge.
The analyses conducted for Task 3 (see Chapters 3 and 4) required the use of the committee’s scientific expertise and judgment, particularly for the 2017 National Academies report recommendations, for which there was a large gap between what was recommended and what occurred during the process to develop the 2020–2025 DGA. In these cases, limited data were available to help predict the form that implementation would have taken, which is critical for determining the expected effects on the DGA. Nonetheless, it was possible for the committee to conclude that the Departments implemented the 2017 National Academies report recommendations that posed the fewest constraints. The Departments were particularly successful in implementing recommendations related to identifying nutrients of concern (recommendation 6) and preparing the systematic reviews (recommendation 4). In addition, the combination of providing more public comment opportunities, improvements in the DietaryGuidelines.gov website and the many documents it made accessible, and an additional open meeting of the DGAC (during which potential conclusions were discussed) increased the transparency of the process (NASEM, 2022b).
There were additional recommendations that the committee regarded as having low barriers to implementation that USDA and HHS did not act on, namely the recommendations for creating and using the TEPs, external reviewers for the systematic reviews, and introducing systems science approaches (recommendations 1, 4, 5, and 7). The use of explicitly constituted TEPs for “content and methodological consultation during the evaluation of the evidence” proposed in recommendation 1 was in the context
of creating the DGSAC. The Departments did not create the DGSAC but constituted a larger DGAC, which served this function of the TEPs. The TEPs had been proposed as a nimble way to bring specific expertise (both federal and nonfederal) into the DGA process to make it more deliberative. Creating TEPs for this purpose would have had a low barrier, but none were implemented in the 2020–2025 DGA cycle.
Although the Departments sought external expertise from other federal groups, including within their own agencies, the committee interpreted the intent of the 2017 National Academies recommendation as a call to obtain expertise from content experts outside of the federal government. However, the committee acknowledges that federal scientists have a wide range of expertise that may be relevant in this situation. The committee thought that it would have been possible to promote a more deliberative and rigorous process by obtaining peer review of the systematic reviews from experts outside of the federal government. The committee agreed with the 2017 National Academies Report that, even without substantial new funding, it would have been possible to introduce systems sciences approaches into the process via a workshop to accelerate the inclusion of these approaches (NASEM, 2017a). USDA received funding in 2022 to develop such a workshop (NASEM, 2022b).
The committee concluded that the Departments did not implement, or at least did not complete implementation of, the 2017 recommendations that would have required more time, effort, and funding than was available during the 2020–2025 DGA cycle. These three recommendations (1, 5, and 7) are expected to make a major difference in key aspects of the DGA process. They still need to be fully implemented to complete the redesign of the DGA process as described in the 2017 National Academies report to address in a timely manner the problems these recommendations were designed to solve.
HOW THE APPROACHES OF USDA AND HHS MEET THE RECOMMENDATIONS FROM THE 2017 NATIONAL ACADEMIES REPORT
As the Departments responsible for producing the DGA, USDA and HHS communicated to the committee that their existing approaches “satisfy goals” of, or have accomplished by other means, the recommendations of the 2017 National Academies report to create the Dietary Guidelines Planning and Continuity Group (DGPCG), TEPs, and DGSAC (see Chapter 4, particularly recommendation 1) (NASEM, 2022b). Moreover, they cite substantial barriers of cost, difficulty, and possible unintended consequences involved in creating these groups as additional reasons for not creating them (Appendix D).
The committee acknowledges that the Departments’ stated barriers are real. The committee considered it outside of its Statement of Task to conduct a detailed cost analysis for the creation and maintenance of the DGPCG, TEPs, and DGSAC. All additions to a budget require justification and the consideration of possible trade-offs, as would the addition of a new committee-governed Federal Advisory Committee Act (FACA). The committee further acknowledges that it is difficult to justify an additional expenditure toward reaching a goal when the entities requesting additional funds—USDA and HHS—perceive the goal to have been substantially accomplished. Moreover, the 2017 National Academies report notes that there may be other mechanisms to address these recommendations (NASEM, 2017a).
Importantly, the Departments introduced and documented numerous changes to their procedures to address the values underlying some of the recommendations, even when they did not implement the recommendation as written. For example, they structured the DGAC and its work to serve the functions for both the DGSAC and the TEPs as described in recommendation 1. As documented in Chapter 4, the Departments see many benefits to their approach.
IMPLEMENTATION OF THE VALUES FROM THE 2017 NATIONAL ACADEMIES REPORT
As noted in this report’s conceptual model (see Chapter 3, Figure 3-1), the desired final outcome of implementation of the 2017 report recommendations is the trustworthiness of the DGA. The committee viewed trustworthiness as a product of the rigor and integrity of the processes used to create the DGA, and therefore focused on rigor and integrity as outcomes. The 2017 report committee identified five values that would improve the integrity of the process and lead to the development of credible and trustworthy guidelines (NASEM, 2017a). These values were to enhance transparency, promote diversity of expertise and experience, support a deliberative process, manage biases and conflicts of interest, and adopt state-of-the-art processes and methods. The proposed redesign of the DGA process was based on these five values, and the current committee viewed its three tasks through the lenses of these values. This perspective is important not only because these values were foundational to the redesign of the process (NASEM, 2017a,b) but also because they are shared by USDA and HHS (DGA, 2018) and also by the current committee.
To improve the transparency of the 2020–2025 DGA process, the Departments made important changes, such as providing additional opportunities for public comment and improving the DietaryGuidelines.gov
website. Since release of the 2020–2025 DGA, USDA and HHS have made further changes to this website to meet the needs of the public (e.g., providing more materials in Spanish) (Stoody and de Jesus, 2022). Nonetheless, the DietaryGuidelines.gov website was difficult for the committee to use to piece together the process by which the DGA were created because there is no seamless navigation (or crosswalk) among the various parts (e.g., systematic reviews, data analysis protocols, the DGAC Scientific Report, or the DGA); information on how the data analyses informed each other was difficult to find, and a detailed description of the process was not provided. Opportunities remain for making further improvements to the transparency of the DGA process. A key opportunity is to provide a public-facing, detailed description and diagram of the overall framework for the DGA process from conception to publication. This resource could include a clear roadmap of who participates in the process, the sources of data that are involved, and how these various inputs (including scientific input from experts who are external to the federal government, as well as public comments) are blended and harmonized, including an analytic framework. The committee believes that a more systematic, structured, and bidirectional communication process with experts, other stakeholders, and the public is required to reach the full benefit of the redesign to the DGA process described in the 2017 National Academies report.
To promote diversity of experience and expertise, the 2020–2025 DGA process—for the first time—included federal-level peer review of the new systematic reviews. The Departments also increased the size of the DGAC to include a range of expertise that aligned with the topics to be covered. Opportunities remain to further involve experts who are external to the federal government, such as including them in the strategic planning for the DGA process as well as an activity to generate topics for inclusion in the DGA, which would involve creation of relevant TEPs and the DGPCG or a group including external experts; peer review of the systematic reviews by external experts; and engagement of experts to bring systems science approaches into the DGA process.
To support a deliberative DGA process, the 2017 National Academies report recognized the need to obtain input from multiple stakeholders (NASEM, 2017a). The term “stakeholder” was used to mean “active partners in the process to update the DGA, including the general public, academia and researchers, advocacy groups, professional organizations, the food sector, and federal agencies” (NASEM, 2017a). That report envisioned a deliberative process as “supporting adaptability, continuity, and continuous learning” (NASEM, 2017a), and sought one that is “adaptive to dynamic shifts in the system in which it operates” (NASEM, 2017a). Many federal agencies are already active participants in various aspects of the process to develop the DGA. The additional opportunities for public
comments provided in the process to develop the 2020–2025 DGA were thought by the agencies to be an effective way of receiving input from several of these groups of stakeholders. However, in the committee’s opinion, inviting input is not sufficient for a full “deliberative” process, which in common usage refers to a two-way discussion. Opportunities remain for further involvement of external scientific input into the DGA process in response to the recommendation that scientists with subject-matter expertise who are outside of the federal government be included in multiple roles in the redesigned process, such as those described in the preceding paragraph. The committee recognizes that some of the ways of obtaining this expertise are subject to restrictions imposed by the FACA and that additional or different approaches may be needed to obtain this expertise.
To manage biases and conflicts of interest (COI), the Departments act at several steps during the systematic review process and elsewhere in the production of the DGA. As noted in Chapter 2, management of COI of individual members of the DGAC committee was updated in response to the 2017 National Academies report (NASEM 2017b). Management of risk of bias as part of NESR’s systematic review process was recently assessed as part of the Continuous Quality Advancement (CQA) program and is generally aligned with practices of other leading systematic review organizations (NASEM 2022a). USDA and HHS have policies that govern COI of individual employees, and for individuals involved in performing systematic reviews. Opportunities remain for the Departments to manage the assessment of any relevant COI.
To adopt state-of-the-art processes and methods, NESR made numerous improvements to the processes and protocols used to create the systematic reviews as part of an ongoing, extensive CQA initiative. Opportunities remain to improve the process used for updating systematic reviews and assessing the quality of evidence. In addition, the framework developed to support the identification of nutrients of concern makes appropriate use of the available data, and robust methods are used in related analyses of the What We Eat In America data (e.g., to account for random error in 24-hour recall data). Given that the Departments were unable to introduce systems science approaches in the development of the 2020–2025 DGA, the opportunity to make these investments remains and has recently begun (Appendix D). These investments are essential to support the ability of the DGA process to provide guidelines that make full use of the available data and to address the diversity of dietary needs and preferences of the U.S. population.
THE COMMITTEE’S OVERALL PERSPECTIVE ON ITS WORK
The federal government has produced nine editions of the DGA. USDA and HHS use “a highly prescribed process” (NASEM, 2022b) to develop these guidelines, which represent many person-years of effort by Departmental staff and external experts who serve on the DGAC. While not without controversy, the DGA provide valued guidance about dietary intake to the public, scientists, healthcare providers, and public health organizations, among others. This guidance is also used by the military and numerous federal programs to develop appropriate feeding standards as well as to estimate the costs of diets. Given its reach, the foundational document must meet the highest standards for scientific rigor and integrity. The 2017 National Academies report committee (NASEM, 2017a) developed recommendations to help the Departments maintain their success and prepare for the future. This report assesses the implementation of those recommendations in the spirit of making a strong process even better.
In the process of conducting its analysis, the committee came to understand that two commonly used terms in its work, “preponderance of evidence” and “best practice,” are not clearly defined. The former has a clear meaning in legal proceedings but not in a scientific context. The latter appears to have a context-specific definition. The lack of both clear and commonly accepted definitions of these terms makes it difficult to conduct the kind of assessment required by the committee’s Statement of Task. Moreover, the resulting lack of clarity may mean that even experts in the field may see the same evidence in different ways.
The Departments received the 2017 National Academies report for redesigning the DGA process after it had begun again and thus limited time and funding were available to address several of its recommendations. To their credit, the Departments made numerous changes in response to the recommendations. These changes included the substantial implementation of recommendations (e.g., recommendation 2—at least in a narrow sense—as well as recommendations 4 and 6). The Departments also implemented alternatives that they considered to be better than certain recommendations and less difficult and costly to implement (e.g., recommendation 1, where the DGAC fulfilled the role of a TEP as well as the DGSAC). Even in these cases, opportunities exist—as described here and in Chapter 4—for further enhancement of the Departments’ responses.
Several issues identified by the 2017 report committee remain, however, and will only become more challenging with each edition of the DGA (NASEM, 2017a). The committee acknowledges that implementing the higher-leverage recommendations is challenging and will require strategic planning by the Departments as well as additional staff effort
and funding. Nonetheless, the committee regards such investments as crucial and urgent given that the DGA are foundational for federal food and nutrition policies and programs and the nation’s health.
There are still opportunities to make these investments in continuing to redesign the structure and process to create the DGA, and in the committee’s opinion, they are essential because the recommendations are expected to be effective and impactful when fully implemented. Moreover, as noted in the 2017 National Academies report:
Redesigning the process is an essential first step, but evaluation will also be needed to understand whether the public trusts the process and, in the long-term, whether adherence to the DGA recommendations actually improves. (NASEM, 2017a)
Dewey, K. G., T. Pannucci, K. O. Casavale, T. A. Davis, S. M. Donovan, R. E. Kleinman, E. M. Taveras, R. L. Bailey, R. Novotny, B. O. Schneeman, J. Stang, J. de Jesus, and E. E. Stoody. 2021. Development of food pattern recommendations for infants and toddlers 6–24 months of age to support the Dietary Guidelines for Americans, 2020–2025. Journal of Nutrition 151(10):3113-3124.
DGA (Dietary Guidelines for Americans). 2018. USDA-HHS response to the National Academies of Sciences, Engineering, and Medicine selecting the Dietary Guidelines Advisory Committee. https://www.dietaryguidelines.gov/sites/default/files/2019-12/USDA%20HHS%20Response%20to%20HMD%20Report%201.pdf (accessed September 22, 2022).
DGAC (Dietary Guidelines Advisory Committee). 2020. Scientific report of the 2020 Dietary Guidelines Advisory Committee. Washington, DC: U.S. Department of Agriculture, Agricultural Research Service.
NASEM (National Academies of Sciences, Engineering, and Medicine). 2017a. Redesigning the process for establishing the Dietary Guidelines for Americans. Washington, DC: The National Academies Press. https://doi.org/10.17226/24883 (accessed September 22, 2022).
NASEM. 2017b. Optimizing the process for establishing the Dietary Guidelines for Americans: The selection process. Washington, DC: The National Academies Press. https://doi.org/10.17226/24637 (accessed September 22, 2022).
NASEM. 2022a. Evaluating the process to develop the Dietary Guidelines for Americans, 2020–2025: A midcourse report. Washington, DC: The National Academies Press. https://doi.org/10.17226/26406 (accessed September 22, 2022).
NASEM. 2022b. Evaluating the process to develop the Dietary Guidelines for Americans, 2020–2025: Committee meeting 34 open session. https://www.nationalacademies.org/event/06-23-2022/evaluating-the-process-to-develop-the-dietary-guidelines-for-americans-2020-2025-committee-meeting-34-open-session (accessed September 22, 2022).
Stoody, E., and J. M. de Jesus 2022. Dietary Guidelines for Americans - An update on implementation of the 2020 edition and status and plans for the 2025 edition. Presented at the American Society of Nutrition Conference. June 2022.