The Dietary Guidelines for Americans (DGA) provides federally developed food-based recommendations for Americans two years of age and older, designed to promote health and prevent disease. As mandated by the 1990 National Nutrition Monitoring and Related Research Act ( P.L. 101-445 ), the guidelines are to be reviewed and updated at least every five years by the Secretaries of the Department of Health and Human Services (HHS) and Agriculture (USDA). The statute requires that the DGA be based on a preponderance of scientific and medical knowledge. This report provides responses to frequently asked questions about the DGA, including the DGA development process, as well as specific recommendations contained in the 2015-2020 DGA. In accord with its statute ( P.L. 101-445 ), the DGA is based on "the preponderance of the scientific and medical knowledge which is current at the time the report is prepared." It is an evidence-based and authoritative policy document that serves as the basis for nutrition policies and programs in the United States, including the National School Lunch Program, the Supplemental Nutrition Assistance Program (SNAP), and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). All federal dietary guidance must be consistent with the DGA. One example of how the DGA has affected public policy is through nutrition labeling. In March 2014, FDA issued two proposed rules to update the Nutrition Facts label based on recommendations contained in the 2010 DGA. More specifically, a key recommendation of the 2010 DGA was to reduce the intake of calories from added sugars, although no quantitative limit was established. In accord with the DGA recommendation, FDA issued a proposed rule that if finalized would, among other things, mandate an "added sugars" line on the Nutrition Facts label, requiring manufacturers to distinguish between added sugars and naturally occurring sugars in food. In July 2015, FDA issued a supplemental proposed rule that would require, in addition to mandatory added sugars labeling, a percent daily value (%DV) declaration for added sugars. In the initial iteration of the proposed rule, FDA proposed mandatory declaration of the amount of added sugars in a food item but not a percent daily value, citing lack of scientific evidence to substantiate such a recommendation. However, the Scientific Report of the 2015 DGAC (2015 DGAC's report) provided new evidence to support establishing a reference amount for added sugar intake. In light of this new evidence, FDA determined that establishing a percent daily value for added sugars was warranted. FDA thereby proposed that the percent daily value should be based on the recommendation that the daily intake of calories from added sugars not exceed 10% of total calories. Over the years, the DGA has evolved from an educational brochure for consumers to a policy document for policy officials, nutritionists, and nutrition educators (see Table 1 ). The eight editions of the DGA have generally contained similar recommendations regarding what constitutes a healthy diet; however, the recommendations have evolved over time to reflect the latest scientific evidence. Although the earlier editions of the DGA contained just seven guidelines, by 2005, that number had increased to 41 (23 for the general public and 18 for specific populations); despite the increase in the number of guidelines, the overarching recommendations have remained largely the same. Beginning in 2020, the DGA is expected to add recommendations for another age cohort (birth to 24 months of age), as directed by a provision in the Agricultural Act of 2014 ( P.L. 113-79 , the "Farm Bill"). The methods used for reviewing evidence to inform the DGA have also changed. In 1980, scientists from HHS (then called the Department of Health, Education, and Welfare) and USDA, along with expertise from the scientific community, were responsible for reviewing the scientific evidence and drafting the DGA. However, following the 1980 DGA's publication, various industry and scientific groups expressed concern regarding the science used to develop the recommendations. To help the departments develop the DGA policy document, a Senate Committee on Appropriations report directed that an external committee be established to review scientific evidence and recommend revisions to the 1980 DGA. In 1983, an external federal advisory committee of nine nutrition scientists was convened to review and make recommendations in a report to the Secretaries of USDA and HHS about the 1980 DGA. Following those recommendations, USDA and HHS released the 1985 DGA (the second edition), which contained almost the same recommendations as the first edition, but was more widely accepted. In 1987, a House Committee on Appropriations conference report directed HHS and USDA to "reestablish a Dietary Guidelines Advisory Group on a periodic basis. This Advisory Group will review the scientific data relevant to nutritional guidance and make recommendations on appropriate changes to the Secretaries of the Departments of Agriculture and Health and Human Services." A Dietary Guidelines Advisory Committee (DGAC) was used in developing the DGA thereafter. The 1995 DGA was the first statutorily mandated ( P.L. 101-445 ) edition of the DGA; the 1980, 1985, and 1990 editions were issued voluntarily by HHS and USDA. Another major change occurred following the 2005 DGA, when the USDA Center for Nutrition Policy and Promotion (CNPP) developed the Nutrition Evidence Library (NEL), which was then used by the 2010 DGAC to systematically review the scientific evidence to inform the development of the 2010 DGA (the NEL is discussed in greater detail in the section " What Is the Nutrition Evidence Library's Role in DGA Development? "). In the first stage of DGA development (see Figure 1 ), a DGAC is chartered following Federal Advisory Committee Act (FACA) guidelines. Within those guidelines, FACA requires that all advisory committees be strictly advisory and prohibits them from creating policy or issuing regulations. The committee is generally composed of nationally recognized experts in the fields of human nutrition, food science, and chronic disease prevention. The experts' work is solely advisory and time-limited. The DGAC provides an advisory scientific report to the Secretaries of HHS and USDA, who consider the report when writing the final DGA policy document. The 2015 DGAC was charged with examining the 2010 DGA, determining topics for which there was new scientific evidence and developing food-based recommendations that are of public health importance for Americans two years of age and older. Through the development process, the DGAC held seven public meetings to review and discuss the scientific evidence supporting the recommendations. To inform the revision of existing recommendations and suggest new guidance, the 2015 DGAC used systematic reviews, data analyses, and/or food pattern modeling analyses, as well as scientific evidence-based reports, input from guest speakers, and public comments. In addition, DGAC relied on the NEL to objectively review, evaluate, and synthesize research to answer nutrition and health questions. In 2008, CNPP established the NEL within its Evidence Analysis Library division to conduct food- and nutrition-related systematic reviews. The "state-of-the-art" systematic review (SR) methodology was developed in consultation with the Agency for Healthcare Research and Quality (AHRQ)--an agency within HHS, and the Academy of Nutrition and Dietetics (AND), and informed by the U.S. Cochrane Collaboration. NEL uses a six-step process to conduct specialized systematic reviews that inform federal nutrition policy and programs. The DGAC uses the NEL process to evaluate the evidence, which the DGAC then uses to inform the development of its Advisory Report. Where needed, NEL staff helped the DGAC carry out some steps of the NEL process. The NEL was created to ensure compliance with the Consolidated Appropriations Act of 2001 ( P.L. 106-554 , the Data Quality Act), which directed the Office of Management of Budget (OMB) to issue government-wide guidelines that "provide policy and procedural guidance to Federal agencies for ensuring and maximizing the quality, objectivity, utility, and integrity of information (including statistical information) disseminated by Federal agencies." In accordance with the first step of the NEL process (see text box), the DGAC identified research questions to be addressed through systematic reviews and developed analytic frameworks to help answer those questions. The DGAC worked with NEL staff to conduct multiple systematic reviews. Once the literature search was completed, two CNPP professionals screened the resulting articles for inclusion criteria to determine whether those articles should be included for review by the DGAC. Throughout this process, the DGAC provided oversight to ensure that studies were being appropriately included or excluded from the review and that the final list of included articles was complete and captured all research available to answer the SR questions. Key information from each study was extracted, and a risk of bias assessment (an assessment of objectivity) was performed by an NEL abstractor. NEL staff reviewed the work of abstractors, resolved inconsistencies, and generated a summary draft of the body of evidence. The DGAC reviewed this work and used it to inform its synthesis of the evidence. Although NEL staff provided oversight and assistance throughout the NEL process, the DGAC made the substantive decisions. One of the final steps in the DGAC's systematic review process was writing and grading a conclusion statement for each question, based on the body of scientific evidence evaluated. The strength of the evidence supporting each conclusion statement was graded using predetermined criteria, which assessed the quality and quantity of studies, the consistency of findings across studies, the generalizability to the population of interest, and the magnitude of the effect or public health impact. On February 15, 2015, the 2015 DGAC submitted its recommendations, as well as the scientific rationale for those recommendations, in a 571-page advisory report to the Secretaries of HHS and USDA. The Secretaries used that report, along with input from other federal agencies and public comments, to develop the final policy document, which was released on January 7, 2016. In developing its recommendations, the 2015 DGAC was guided by "two fundamental realities": (1) the high prevalence of preventable chronic disease among U.S. adults, and (2) the assumption that individuals' nutrition, physical activity, and other lifestyle-related behaviors are strongly influenced by their personal, social, organizational, and environmental contexts. As a result of these "realities," the DGAC framed its evidence review in the context of a socioecological model, examining how individual nutrition, physical activity, and other health-related lifestyle behaviors are influenced by personal, social, organizational, and environmental factors and systems. Many recommendations contained in the 2015 DGAC's report were consistent with those of the 2010 DGA. For example, the 2015 DGAC's report concluded that a healthy dietary pattern is higher in vegetables, fruits, whole grains, low- or non-fat dairy, seafood, legumes, and nuts; moderate in alcohol (among adults); and low in sugar-sweetened foods and beverages and refined grains. These recommendations are consistent with the 2010 DGA recommendations to increase fruit and vegetable intake; consume at least half of all grains as whole grains; increase intake of fat-free or low-fat milk and milk products; and choose a variety of protein foods including seafood, lean meat and poultry, eggs, beans and peas, soy products, and unsalted nuts and seeds. The 2015 DGAC's report and the 2010 DGA both advised using oils to replace saturated fats and consuming seafood in place of some meat and poultry. In addition, the 2015 DGAC determined that coffee consumption within the moderate range (three to five cups, or 400 mg, per day) is not associated with increased risk of major chronic diseases; dietary cholesterol does not appear to be associated with serum cholesterol (thus the committee did not bring forward the previous recommendation to limit cholesterol to 300 mg per day); added sugar intake should be limited to less than 10% of total daily calories; and healthy dietary patterns are lower in red and processed meat. The DGAC report also contained various recommendations related to establishing healthy food environments (e.g., school meals, front-of-package nutrition labeling, and industry product reformulation), sustainability (i.e., concluding that a plant-based diet is not only more health promoting but also better for the environment), and tax policy (e.g., taxing sugar-sweetened beverages). The DGAC's report addressed many issues of concern to public health, nutrition, and agricultural stakeholders. HHS and USDA received over 29,000 written comments during the 75-day comment period, as well as 73 oral comments at a March 2015 public meeting. Stakeholders flagged several issues with the 2015 DGAC's report, particularly with the scope of the DGAC's recommendations, the process by which the DGAC made its conclusions and recommendations, and concerns over several specific recommendations. One concern noted by stakeholders with the DGAC's report was its scope, with some maintaining that the committee exceeded the scope of its charter by making certain policy recommendations. For example, although the 2015 DGAC's report noted that no food groups need to be entirely eliminated to improve food sustainability outcomes, the DGAC concluded that individuals should eat less red and processed meat in favor of a plant-based diet, as "a diet higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in calories and animal-based foods is more health promoting and is associated with less environmental impact than is the current U.S. diet." The DGAC added that due to high consumption of animal-based foods (e.g., meat, eggs, and dairy products) and low intake of plant-based foods, the average U.S. diet may have a large impact on the environment in terms of increased Greenhouse Gas (GHG) emissions, land use, water use, and energy use. In addition, the DGAC made several policy recommendations that raised concern among some stakeholders, including FDA revision of the Nutrition Facts label to include a mandatory declaration for added sugars, in both grams and teaspoons per serving, as well as a % daily value (DV); alignment of federal nutrition assistance programs (e.g., SNAP and WIC) with the DGA; and use of economic and tax policies to encourage the production and consumption of healthy foods and to reduce consumption of unhealthy foods (e.g., by taxing sugar-sweetened beverages, snack foods, and desserts, and by restricting marketing of certain foods to children and teens). Some Members of Congress have said that the DGAC "had neither the expertise, evidence, nor charter" to make recommendations about matters of sustainability and tax policy, and this concern has been reiterated by some meat industry groups. Meanwhile, others have supported the discussion surrounding sustainability, saying that it is important to have an understanding of how food production affects the environment. In response to these concerns, the HHS and USDA Secretaries determined that issues of sustainability and tax policy would not be part of the final policy document and that the DGA would "remain within the scope of our mandate in the 1990 National Nutrition Monitoring and Related Research Act ( P.L. 101-445 , NNMRRA), which is to provide 'nutritional and dietary information and guidelines' ... 'based on the preponderance of the scientific and medical knowledge.'" Another stakeholder concern with the 2015 DGAC's report was the process used to evaluate the evidence. After the 2005 edition of the DGA, HHS and USDA committed to using an evidence-based, systematic review methodology (i.e., the NEL) to support the development of the 2010 DGAC report, and the same process was expected to be used in the development of the 2015 DGAC report. The 2015 DGAC used the NEL to answer approximately 27% of its questions, relying on existing sources of evidence (e.g., existing reports and systematic reviews) to answer another 45%, and data analyses and food pattern modeling analyses to answer an additional 30%. This approach is in contrast to the 2010 DGAC, which used the NEL to answer the majority of its research questions. According to the 2015 DGAC, the majority of the scientific community now regularly uses systematic reviews, so unlike the 2010 DGAC, the 2015 DGAC was able to rely more heavily on existing sources of evidence (e.g., existing systematic reviews, meta-analyses, and reports) and to avoid duplicative efforts. Some criticized this use of existing reviews, questioning the scientific rigor and objectivity of the advisory report. For example, some argued that the 2015 DGAC bypassed the NEL process for certain issues (e.g., added sugars) and "almost solely used pre-existing and hand-picked systematic reviews." Others voiced concern that the 2015 DGAC relied heavily on weaker forms of science, such as observational evidence rather than the whole body of evidence. In addition to the scope of the 2015 DGAC report and the committee's process, certain recommendations were criticized by various stakeholders and interest groups. For example, the 2015 DGAC concluded that diets lower in red and processed meat are more healthful and better for the environment. The recommendation to reduce consumption of red and processed meat was met with concern from some meat industry groups, who cited that meat is a nutrient-dense source of protein, including nutrients such as iron and B vitamins. The 2015 DGAC also concluded that intake of added sugars from sugar-sweetened beverages and foods is associated with excess body weight in children and adults. Although a daily value for added sugar had not been established, strong and consistent evidence demonstrates that a reduction of added sugars is associated with a reduction in body mass index (BMI) in both children and adults. Thus, the 2015 DGAC recommended that intake of added sugars remain below 10% of total calorie intake. This recommendation was consistent with the 2010 DGA recommendation to reduce the intake of calories from solid fats and added sugars. In regard to the added sugars recommendation, some food industry groups argued that there is a lack of evidence to justify a label that distinguishes between naturally occurring and added sugars because all sugars are equivalent in a nutritional sense, and because there is not enough evidence to establish a quantitative limit on added sugars. The 2015-2020 DGA consists of five overarching guidelines, which are accompanied by "Key Recommendations" that provide further guidance on how individuals can follow the guidelines. Per the 2015-2020 DGA, the eating pattern described is not meant to be a "rigid prescription" but rather an "adaptable framework in which individuals can enjoy foods that meet their personal, cultural, and traditional preferences and fit within their budget." 1. Follow a healthy eating pattern across the lifespan . All food and beverage choices matter. Choose a healthy eating pattern at an appropriate calorie level to help achieve and maintain a healthy body weight, support nutrient adequacy, and reduce the risk of chronic disease. 2. Focus on variety, nutrient density, and amount. To meet nutrient needs within calorie limits, choose a variety of nutrient-dense foods across and within all food groups in recommended amounts. 3. Limit calories from added sugars and saturated fats and reduce sodium intake. Consume an eating pattern low in added sugars, saturated fats, and sodium. Cut back on foods and beverages higher in these components to amounts that fit within healthy eating patterns. 4. Shift to healthier food and beverage choices. Choose nutrient-dense foods and beverages across and within all food groups in place of less healthy choices. Consider cultural and personal preferences to make these shifts easier to accomplish and maintain. 5. Support healthy eating patterns for all . Everyone has a role in helping to create and support healthy eating patterns in multiple settings nationwide, from home to school to work to communities. The 2015-2020 DGA includes the recommendation to "consume a healthy eating pattern that accounts for all foods and beverages within an appropriate calorie level." A healthy eating pattern is described as one that includes a variety of vegetables from all the subgroups--dark green, red and orange, legumes (beans and peas), starchy, other; fruit, especially whole fruits; grains, at least half of which are whole grains; fat-free or low-fat dairy, including milk, yogurt, cheese, and/or fortified soy beverages; a variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products; and oils. A healthy eating pattern limits saturated fats and trans fats, added sugars, and sodium. This eating pattern includes consuming less than 10% of calories per day from added sugars, less than 10% of calories per day from saturated fats, and less than 2,300 milligrams (mg) per day of sodium. If alcohol is consumed, it should be in moderation (one drink for women, two drinks for men) and only by those of legal drinking age. In addition, the 2015-2020 DGA includes the recommendation to meet the Physical Activity Guidelines for Americans (PGA). The PGA states that adults need at least 150 minutes of moderate intensity physical activity per week and should perform muscle-strengthening exercises on two or more days each week. Children and adolescents 6 to 17 years of age need at least 60 minutes of physical activity per day, including aerobic, muscle-strengthening, and bone-strengthening activities. The 2015-2020 DGA does not include a key recommendation to reduce consumption of red and processed meat as advised by the 2015 DGAC report. Chapter 1 of the 2015-2020 DGA states that strong evidence has shown that eating patterns with lower meat intake, including processed meat and lean process poultry, are associated with reduced risk of cardiovascular disease in adults. However, food pattern modeling analyses have shown that lean meats and lean poultry contribute important nutrients to a diet, and healthy eating patterns may include processed meats and poultry, within the daily limits for sodium, calories from saturated fats and added sugars, and calories. The text of the 2015-2020 DGA states that coffee consumption in the moderate range (e.g., up to 400 mg of caffeine per day, or approximately 3 to 5 cups of coffee) may be incorporated into healthy eating patterns. The DGA adds that although coffee has minimal calories, coffee beverages often contain added sweeteners and creams, which should be limited to avoid adding extra calories; these same considerations apply to tea and other similar beverages. The 2015-2020 DGA does not differentiate between different sources of caffeine (e.g., coffee, tea, soda), but much of the available evidence on caffeine focuses on coffee intake; limited and mixed evidence is available regarding the relationship between high caffeine energy drinks and cardiovascular risk factors and other health outcomes. The 2015-2020 DGA also states that mixing caffeine with alcohol is not generally recognized as safe by FDA, and increases the risk of alcohol-related adverse events. The 2015-2020 DGA does not contain the 2010 DGA recommendation to limit daily dietary cholesterol (a nutrient found in animal products; examples include shrimp, eggs, and meat) consumption to less than 300 mg per day, stating a lack of adequate evidence for a quantitative limit for dietary cholesterol specific to the DGA. The 2015-2020 DGA retains many of the recommendations made by the 2010 DGA, as well as those suggested by the 2015 DGAC's report. For example, the 2015-2020 DGA's definition of a healthy eating pattern is largely consistent with the patterns described in the 2010 DGA and the 2015 DGAC report. Similarly, recommendations about which nutrients to limit have remained consistent across the three documents, with some exceptions: the 2010 DGA recommended a quantitative daily limit on cholesterol, but the 2015-2020 DGA and 2015 DGAC's report did not; the 2015-2020 DGA and 2015 DGAC's report recommended a quantitative daily limit on added sugars, but the 2010 DGA did not (see Table 2 ). Further, the 2015-2020 DGA does not include references to sustainability or tax policy, as suggested in the 2015 DGAC's report. In response to stakeholder concern surrounding the scope of the 2015 DGAC's report and the process used to develop the 2015-2020 DGA, Congress included several DGA-related policy riders in the FY2016 Omnibus Appropriations Act ( P.L. 114-113 ). Section 734 limited the scope of the 2015-2020 DGA to "nutritional and dietary information only." Section 735(a) required the Secretary of USDA, within 30 days of the enactment of the law, to engage the National Academy of Medicine (NAM, formerly the Institute of Medicine [IOM]) to conduct a comprehensive study of the process used to establish the 2015 DGAC and the subsequent development of the 2015 DGA. Section 735(b) further required that the NAM panel selected to conduct this study include a "balanced representation of individuals with broad experiences and viewpoints regarding nutrition and dietary information," and that this comprehensive study include an analysis of how the DGA can better prevent chronic disease, ensure nutritional adequacy for all Americans, and accommodate a range of individual factors, including age, gender, and metabolic health; the DGAC selection process "can be improved to provide more transparency, eliminate bias, and include committee members with a range of viewpoints"; the NEL is compiled and used, including whether NEL and other systematic reviews, as well as data analyses, are conducted following "rigorous and objective scientific standards"; and systematic reviews are conducted on "longstanding" DGA recommendations, including "whether scientific studies are included from scientists with a range of viewpoints." Section 735(b) also requires the NAM study to include recommendations on how to improve the DGA development process and to ensure the DGA "reflect balanced and sound science." Congress appropriated $1 million for this study. It remains to be seen how, if at all, the DGA development process will change pursuant to the findings of the congressionally mandated NAM study. In addition to any recommendations following NAM's mandated study, the 2020-2025 DGA will expand to include infants and toddlers from birth to age two, as well as additional guidance for women who are pregnant, as required by the 2014 Agricultural Appropriations Act ( P.L. 113-79 ).

Summary:
The Dietary Guidelines for Americans (DGA) is a policy document that provides federally developed, nutrition-based recommendations for Americans two years of age and older. The guidelines are statutorily mandated under the 1990 National Nutrition Monitoring and Related Research Act (P.L. 101-445), which requires the Departments of Health and Human Services (HHS) and Agriculture (USDA) to jointly publish the DGA policy document at least once every five years. The DGA forms the basis for all federal nutrition policies, including the National School Lunch Program and the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). The guidelines also influence food and nutrition labeling; guide local, state, and national health promotion and disease prevention initiatives; and inform various organizations and industries (e.g., products developed and marketed by the food and beverage industry). To facilitate publication of the DGA policy document, a conference report from the House Committee on Appropriations directed HHS and USDA to establish a Dietary Guidelines Advisory Committee (DGAC) on a periodic basis. The DGAC is an independent group of experts from outside the federal sector, generally in the fields of nutrition and medicine, whose work is solely advisory and time-limited. The DGAC is tasked with reviewing the scientific data relevant to nutritional guidance and making recommendations to the Secretaries of HHS and USDA regarding changes to the DGA policy document. The 571-page Scientific Report of the 2015 DGAC (2015 DGAC's report) was made public on February 19, 2015, and was used by the departments, along with public comments and input from other federal agencies, to inform the drafting of the 2015-2020 DGA policy document. Because the DGA influences nutrition policy, the guidelines are of interest to public health, nutrition, agriculture, and food industry stakeholders. Following the release of the 2015 DGAC's report, HHS and USDA received 29,000 written comments during the 75-day comment period, as well as 73 oral comments at a March 2015 public meeting. Stakeholders flagged several concerns with the report, particularly with the scope of the DGAC's recommendations and the process by which the DGAC made its conclusions and recommendations, along with concerns regarding several specific recommendations. In response to concerns surrounding the scope of the 2015 DGAC's report and the process used to develop the 2015-2020 DGA, several DGA-related policy riders were included in the FY2016 omnibus appropriations law (P.L. 114-113), prior to the release of the 2015-2020 DGA. As mandated by Congress, the National Academies of Medicine (NAM) are, for the first time, required to review the DGA and its development process due to concerns with the "quality of scientific evidence and extraneous factors" that were included in the 2015 DGAC's report. HHS and USDA issued the 2015-2020 DGA on January 7, 2016. This most recent DGA provides five overarching guidelines for the general population, accompanied by several "Key Recommendations" that provide further guidance on how individuals can follow the five guidelines.