IntroductionPrint this section
Developing the Dietary Guidelines for Americans
In this section:
A greater understanding of the relationships between nutrition and human health has and will continue to evolve over time. Creating each edition of the Dietary Guidelines is a joint effort of HHS and USDA. A new edition is published every 5 years to reflect advancements in scientific knowledge and translate the science current at the time into sound food-based guidance to promote health in the United States. The process to develop the Dietary Guidelines has also evolved and includes three stages.
Figure I-3. Science, Policy, Implementation:
Developing the 2015-2020 Dietary Guidelines for Americans
To develop each edition of the Dietary Guidelines for Americans, HHS and USDA collaborate during a 3-stage process.
1Review the Science
First, an external Advisory Committee creates the Advisory Report and submits it to the Secretaries of HHS and USDA.
This report is informed by:
- Original systematic reviews
- Review of existing systematic reviews, meta-analyses, and reports by federal agencies or leading scientific organizations
- Data analyses
- Food pattern modeling analyses
2Develop the Dietary Guidelines
Using the previous edition of the Dietary Guidelines, the Advisory Report, and consideration of public and federal agency comments, HHS and USDA develop a new edition of the Dietary Guidelines. The 2015-2020 Dietary Guidelines for Americans includes:
3Implement the Dietary Guidelines
Federal programs apply the Dietary Guidelines to meet the needs of Americans through food, nutrition, and health policies and programs—and in nutrition education materials for the public.
Stage 1: Review of Current Scientific Evidence
In the first stage, the Secretaries of HHS and of USDA appoint an external Dietary Guidelines Advisory Committee (Advisory Committee). The use of a Federal advisory committee is to ensure the Federal Government is seeking sound external scientific advice to inform policy decisions. Nominations from the public were sought for candidates to serve on the 2015 Advisory Committee. The 15 members of the 2015 Advisory Committee are prestigious researchers in the fields of nutrition, health, and medicine. Their role was to provide advice and recommendations to the Federal Government on the current state of scientific evidence on nutrition and health. Per Federal Advisory Committee Act rules, Advisory Committee members were thoroughly vetted for conflicts of interest before they were appointed to their positions and were required to submit a financial disclosure form annually.
The 2015 Advisory Committee was charged with reviewing the 2010 edition of the Dietary Guidelines to determine the topics for which new scientific evidence was likely to be available, and to review that evidence to inform the development of the 2015-2020 edition. The Advisory Committee was asked to place primary emphasis on evidence published since the 2010 Advisory Committee completed its work and on evidence to support the development of food-based recommendations that are of public health importance for Americans ages 2 years and older. It met in public meetings to discuss its findings and develop its recommendations. The public was invited to submit written comments to the Advisory Committee throughout the entirety of its work as well as oral comments at a public meeting.
The 2015 Advisory Committee used four state-of-the-art approaches to review and analyze the available evidence: original systematic reviews; existing systematic reviews, meta-analyses, and reports by Federal agencies or leading scientific organizations; data analyses; and food pattern modeling analyses. Most of its conclusion statements on nutrition and health were informed by systematic reviews, which are a gold standard for informing clinical practice guidelines and public health policies worldwide. The Dietary Reference Intakes (DRIs), as set by the Institute of Medicine (IOM), also serve as a source of evidence for the Advisory Report and the Dietary Guidelines. This multifaceted approach allowed the Advisory Committee to ask and answer scientific questions about the relationship of diet and health to systematically, objectively, and transparently synthesize research findings and to limit bias in its evaluation of the totality of the evidence for the topics it reviewed. This approach also allowed one or more methods to be used that were best suited to comprehensively answer each question. These methods are described below.
Original systematic reviews. The Advisory Committee used this approach to systematically search the scientific literature for relevant articles; assess the methodologic rigor of each included article; and summarize, analyze, and grade the evidence presented in the articles.
For systematic reviews, all studies published by the time the literature search was conducted were screened for inclusion to ensure all available evidence was reviewed in a systematic manner. To preserve the integrity of the process, individual studies that were published after the systematic review was concluded were not included on an ad hoc basis. Recent studies that were not included in the 2015 Advisory Committee’s review will be available for consideration during the development of the next edition of the Dietary Guidelines.
The USDA Nutrition Evidence Library (NEL) uses a systematic review methodology designed to analyze food, nutrition, and public health science. The medical field has used systematic reviews as the standard practice for more than 25 years to inform the development of national guidelines for health professionals.
Review of existing systematic reviews, meta-analyses, and reports by Federal agencies or leading scientific organizations. The Advisory Committee used this method when a high-quality existing review or report had already addressed a question under consideration. The approach involved applying a systematic process to assess the quality of the existing review or report and to ensure that it presented a comprehensive review of the Advisory Committee’s question of interest.
At the time that the NEL was created by USDA for use in informing the 2010 Dietary Guidelines, it was among the first to apply the systematic review methodology in the field of nutrition. Thus, very few existing nutrition-focused systematic reviews were available for the 2010 Advisory Committee to use. Since that time, systematic reviews in the nutrition field have become common practice. Therefore, unlike the 2010 Advisory Committee, the 2015 Advisory Committee was able to use existing reviews to answer many of its research questions, preventing duplication of effort. Existing systematic reviews underwent quality assessment to ensure they were just as rigorous and were held to the same high standards as the systematic reviews conducted through the NEL.
Data analyses. The Advisory Committee used national data from Federal agencies to answer questions about chronic disease prevalence rates; food and nutrient intakes of the U.S. population across age, sex, and other demographic characteristics; and nutrient content of foods.
For other questions, a new analysis from existing data sets was requested from the appropriate Federal agency to provide the answer to the question posed. Data analyses tailored to a specific question helped inform the Advisory Committee’s recommendations.
Food pattern modeling analyses. The Advisory Committee used this method to estimate the effect on diet quality of possible changes in types or amounts of foods in the USDA Food Patterns that it was considering recommending. The USDA Food Patterns describe the types and amounts of foods to eat that can provide a healthy and nutritionally adequate diet. The Food Patterns aim to meet the DRIs while taking into consideration current intakes in the United States and systematic reviews of scientific research. They were developed to demonstrate how Dietary Guidelines recommendations can be met within an overall eating pattern.
Food pattern modeling analyses guided by the Advisory Committee provided objective information on the potential nutritional effects of recommending an eating pattern with specific changes, such as selecting foods to increase vitamin D intake or modifying the pattern based on studies of Mediterranean diets. The results of the modeling analyses informed the Committee’s recommendations on specific topics, including keeping recommendations grounded within the structure of an overall healthy eating pattern.
As part of its assessment of evidence on diet and health, the Committee also formulated recommendations for future research. These research recommendations reflect an acknowledgment that knowledge about nutrition, diet, and health associations continues to evolve and that new findings build on and enhance existing evidence.
The Advisory Committee’s work culminated in the Scientific Report of the 2015 Dietary Guidelines Advisory Committee, which was submitted to the Secretaries of HHS and of USDA and made available for public and agency comment in February 2015. For more information about the Advisory Committee and its review process and Advisory Report, visit https://health.gov/our-work/food-nutrition/.
Stage 2: Development of the Dietary Guidelines for Americans
In the second stage, HHS and USDA develop the policy document Dietary Guidelines, applying several process steps to promote scientific rigor. Similar to previous editions, this 8th edition builds upon the preceding edition, with the scientific justification for revisions informed by the Advisory Committee’s report and consideration of public and Federal agency comments.
As previously mentioned, the public is invited to submit written comments to the Advisory Committee throughout the entirety of its work as well as oral comments at a public meeting. In addition, after the Advisory Committee’s report was submitted to the Secretaries, the public is again invited to submit written comments to the Federal Government on the Advisory Committee’s final report as well as oral comments at a public meeting. Comments on the Advisory Committee’s report are considered in the development of the policy document, placing emphasis on those with scientific justification while ensuring that the policy is based on the totality of the evidence and not on individual studies.
Federal agencies within HHS and USDA have extensive, broad scientific expertise in nutrition and health, as well as experts who specialize in unique aspects of nutrition and health. Federal experts validate the rigor of the policy document in multiple ways. After the Advisory Committee’s report is complete, Federal agencies provide comments regarding the applicability and rigor of the report for consideration in translating the science into policy. Those who update the policy document are Federal experts with specialized knowledge in the evidence under consideration and its policy applications within the Federal Government. These policy writers include nutrition scientists, policy experts, and communications specialists. Consultation with other Federal experts occurs throughout the policy development process.
A peer-review step also is completed, in which nonfederal experts independently conduct a confidential review of the draft policy document for clarity and technical accuracy of the translation of the evidence from the Advisory Report into policy language. In addition, extensive review and clearance of the policy document also occurs by Federal experts within the agencies of both Departments. The Federal clearance of the policy document culminates with review and approval by the Secretaries of HHS and of USDA.
The 2015-2020 Dietary Guidelines is built around five Guidelines with accompanying Key Recommendations that provide detail on the elements of healthy eating patterns. The Key Recommendations represent the preponderance of the most current scientific evidence. Emphasis is placed on topics with the strongest evidence or public health need, indicating a low likelihood that new or additional evidence would greatly change the recommendation. Ultimately, the Dietary Guidelines aims to represent the current science on diet and health, provide food-based guidance that meets nutrient needs, and address areas of particular public health importance in the United States.
Looking Ahead to 2020—Expanding Guidancemore▼
Describing the Strength of Evidence Supporting Recommendations
Considerable evidence demonstrates that a healthy diet and regular physical activity can help improve health and reduce the risk of certain chronic diseases. Throughout, the 2015-2020 edition of the Dietary Guidelines notes the strength of evidence supporting its recommendations. This information is provided to show how much evidence is available and how consistent the evidence is for a particular statement or recommendation:
Strong evidence reflects a large, high-quality, and/or consistent body of evidence. There is a high level of certainty that the evidence is relevant to the population of interest, and additional studies are unlikely to change conclusions derived from this evidence. Topics that are supported by strong evidence often lead to policy recommendations with the greatest emphasis because of the confidence generated by the evidence.
Moderate evidence reflects sufficient evidence to draw conclusions. The level of certainty may be restricted by certain limitations in the evidence, such as the amount of evidence available, inconsistencies in findings, or limitations in methodology or generalizability. Topics that are supported by moderate evidence can support recommendations of varying emphasis, including complementing those with a strong evidence base.
Limited evidence reflects either a small number of studies, studies of weak design or with inconsistent results, and/or limitations on the generalizability of the findings. When only limited evidence is available on a topic, it is insufficient to inform Key Recommendations. However, policy statements are sometimes useful for topics that have limited supporting evidence, such as when the evidence for those topics reinforces recommendations on related topics that have a stronger evidence base, to clarify that it is not possible to make a recommendation, or to identify an area of emerging research.
The evidence described in the Dietary Guidelines also reflects an understanding of the difference between association and causation. Two factors may be associated; however, this association does not mean that one factor necessarily causes the other. Often, several different factors may contribute to a health outcome. In some cases, scientific conclusions are based on relationships or associations because studies examining cause and effect are not available.
Stage 3: Implementing the Dietary Guidelines for Americans
In the third and final stage, the Federal Government implements the recommendations in the Dietary Guidelines. Federal programs apply the Dietary Guidelines to meet the needs of Americans and specific population groups through food, nutrition, and health policies and programs and in nutrition education materials for the public. Although the Dietary Guidelines provides the foundation for Federal nutrition and health initiatives, it is each Federal agency’s purview and responsibility to determine how best to implement the Dietary Guidelines to serve its specific audiences. For example, one way USDA and other Federal agencies can implement the Dietary Guidelines is through MyPlate, which serves as a reminder to build healthy eating patterns by making healthy choices across the food groups. Both Federal and nonfederal programs may use MyPlate as a resource to help Americans make shifts in their daily food and beverage choices to align with the Dietary Guidelines. For more information about Dietary Guidelines implementation for the public through MyPlate, see Chapter 3. Everyone Has a Role To Play in Supporting Healthy Eating Patterns and Figure 3-2.
Implementation of the Dietary Guidelines Through MyPlatemore▼
The Dietary Guidelines recognizes that many factors influence the diet and physical activity choices individuals make. The United States is a highly diverse nation, with people from many backgrounds, cultures, and traditions, and with varied personal preferences. It also acknowledges that income and life circumstances play a major role in food and physical activity decisions. Significant health and food access disparities exist, with nearly 15 percent of U.S. households unable to acquire adequate food to meet their needs because of insufficient income or other resources for food. These factors—along with the settings in which people live, learn, work, and play—can have a profound impact on their choices.
In addition to implementation by the Federal Government and as discussed in Chapter 3, ample opportunities exist for many other sectors of society to implement the Dietary Guidelines in the multiple settings they influence, from home to school to work to community.
Aligning With the Dietary Guidelines for Americans: What Does This Mean in Practice?more▼
 Public Law 101-445, Title III, Section 301, 7 U.S.C. 5341 et seq. requires that the U.S. Departments of Health and Human Services and of Agriculture publish a new edition of the Dietary Guidelines for Americans every 5 years.
 If not specified explicitly, references to “foods” refer to “foods and beverages.”
 U.S. Department of Agriculture. Economic Research Service. Food security in the U.S. Key Statistics and Graphics. [Updated September 8, 2015.] Available at http://www.ers.usda.gov/topics/food-nutrition-assistance/food-security-in-the-us/key-statistics-graphics.aspx Accessed June 10, 2015.