Linda G. Snetselaar, PhD, RDN, FAND, is a professor in epidemiology at the College of Public Health and a secondary faculty in endocrinology at Carver College of Medicine at the University of Iowa. Linda served on the 2020 Dietary Guidelines Scientific Advisory Committee, Iowa City, IA.
Janet M. de Jesus, MS, RD, is a nutrition advisory in the Office of Disease Prevention and Health Promotion at the US Department of Health and Human Services (HHS) where she serves as the HHS lead for the Dietary Guidelines for Americans development and participates in other cross-cutting federal nutrition activities in Rockville, Maryland.
Dana M. DeSilva, PhD, RD, is a health policy fellow in the Office of Disease Prevention and Health Promotion at the US Department of Health and Human Services, where she assists in the coordination, development, and communication of the Dietary Guidelines for Americans, in Rockville, Maryland.
Eve E. Stoody, PhD, is the Director of the Office of Nutrition Guidance and Analysis of USDA's Center for Nutrition Policy and Promotion. Eve served as the USDA staff lead in the development of the 2020-2025 Dietary Guidelines for Americans and designated federal officer to the 2020 Dietary Guidelines Advisory Committee, Alexandria, VA.
Correspondence: Linda G. Snetselaar, PhD, RDN, FAND, College of Public Health Building, University of Iowa, 145 N Riverside Dr, Iowa City, IA 52242 (ude.awoiu@raalestens-adnil).
Copyright © 2021 The Authors. Published by Wolters Kluwer Health, Inc.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
The Dietary Guidelines for Americans, 2020–2025 was issued jointly by the US Departments of Agriculture and of Health and Human Services in December 2020. It is the ninth edition of the Dietary Guidelines and is the first to provide recommendations by life stage, from birth to older adulthood. The Dietary Guidelines is grounded in the current body of scientific evidence on diet and health outcomes and aims to promote health and prevent chronic diseases. The process to develop the Dietary Guidelines involved 4 steps: (1) identifying the topics and supporting scientific questions, (2) appointing a Dietary Guidelines Advisory Committee (Committee) to review current scientific evidence, (3) developing the new edition of the Dietary Guidelines, and (4) implementing the Dietary Guidelines. The 2020-2025 edition provides 4 overarching guidelines and supporting key recommendations that encourage healthy dietary patterns across the life span. The foods and beverages that people consume have a profound impact on health, and it is never too late or too early to eat healthfully.
The Dietary Guidelines for Americans, 2020–2025 (Dietary Guidelines) includes an important call to action for health professionals and policymakers, to help the public “make every bite count.” 1 This article provides an overview of the recommendations in the recent edition and background on the scientific review process that informed the development of the Dietary Guidelines.
The US Departments of Agriculture (USDA) and of Health and Human Services (HHS) update the Dietary Guidelines every 5 years, based on the current science. Although many recommendations have remained relatively consistent over time, the Dietary Guidelines also has evolved as scientific knowledge has grown. The 2020–2025 Dietary Guidelines for Americans reflects this in 3 important ways. The first is its recognition that diet-related chronic diseases, such as cardiovascular disease, type 2 diabetes, obesity, and some types of cancer, are very prevalent among Americans and pose a major public health problem. A fundamental premise of the Dietary Guidelines is that everyone, no matter their age, race, or ethnicity, economic circumstances, or health status, can benefit from shifting food and beverage choices to better support healthy dietary patterns. The second is its focus on dietary patterns. Researchers and public health experts understand that nutrients and foods are not consumed in isolation. Rather, people consume them in various combinations over time—a dietary pattern—and these foods and beverages act synergistically to affect health. The 2020–2025 Dietary Guidelines carries forward this emphasis on the importance of a healthy dietary pattern as a whole—rather than on individual nutrients, foods, or food groups in isolation. The third is its focus on a life span approach. This edition of the Dietary Guidelines highlights the importance of encouraging healthy dietary patterns at every life stage from infancy through older adulthood. For the first time since the 1985 edition, the 2020–2025 Dietary Guidelines includes recommendations for healthy dietary patterns for infants and toddlers.
The Dietary Guidelines provides science-based advice on what to eat and drink to promote health, help reduce the risk of chronic disease, and meet nutrient needs. It serves as the cornerstone of federal nutrition programs and policies and is mandated by law to reflect the preponderance of scientific evidence and to be published by USDA and HHS at least every 5 years. 2
As an important part of a complex, multifaceted approach to promote health and reduce chronic disease risk, the Dietary Guidelines is written for a professional audience, including policymakers, healthcare professionals, nutrition educators, and federal nutrition program operators. Health professionals are a critically important audience who work with the public to help them consume a healthy and nutritionally adequate diet. Comprehensive, coordinated strategies built on the science-based foundation of the Dietary Guidelines—and a commitment to drive these strategies over time across sectors and settings—can help all Americans consume healthy dietary patterns, achieve and maintain good health, and reduce the risk of chronic diseases.
The process to develop the Dietary Guidelines has evolved over time, in step with developments in nutrition science, public health, and best practices in scientific review and guidance development. In establishing the process for the 2020–2025 Dietary Guidelines, USDA and HHS considered and integrated recommendations from a comprehensive 2017 National Academies' study, “Review of the Process to Update the Dietary Guidelines.” 3 Greater transparency figured prominently in the Academies' recommendations. As a result, USDA and HHS made significant changes to increase transparency and public participation while maintaining the core element of scientific integrity.
The 2020–2025 process consisted of 4 stages: (1) identifying the topics and supporting scientific questions to be examined, (2) appointing a Dietary Guidelines Advisory Committee (Committee) to review current scientific evidence and develop a scientific report, (3) developing the new edition of the Dietary Guidelines, and (4) implementing the Dietary Guidelines through federal programs and nonfederal program entities (Figure (Figure1 1 ).
The four stages of the process to develop the Dietary Guidelines for Americans.
The Departments added a new first step of identifying topics and scientific questions to begin the process of developing the next Dietary Guidelines. This step was added to promote a deliberate and transparent process, better define the expertise needed on the Committee, ensure the scientific review conducted by the Committee would address federal nutrition policy and program needs, and help manage resources. Topics and questions were made available for the public to view and provide comments. The USDA and HHS considered each public and agency comment to refine the topics and questions. Final topics and questions were posted along with the public call for nominations to the 2020 Dietary Guidelines Advisory Committee.
In the second stage, the Secretaries of USDA and HHS appointed the Committee with the single, time-limited task of reviewing the 2015–2020 Dietary Guidelines, examining the evidence on the selected nutrition and public health topics and scientific questions, and providing independent, science-based advice and recommendations to USDA and HHS. The Committee was announced in February and appointed at the first public meeting in March 2019. Public comments were accepted throughout the process. The Committee met a total of 6 times. The Committee timeline was extended by 1 month because of the impact of COVID-19 (Figure (Figure2 2 ).
The 2020 Dietary Guidelines Advisory Committee timeline.
The 20 nationally recognized scientific experts appointed to the Committee represented a mix of practitioners, epidemiologists, scientists, clinical trial experts, and others from every region of the United States. This is the largest Committee to date because of the additional emphasis on infants, toddlers, and pregnant women. The Committee members were selected on predetermined criteria including educational background, professional experience, scientific expertise, obligations under the Federal Advisory Committee Act, and requirements regarding a balanced membership. The USDA and HHS not only examined nomination packages individually to ensure each person met the criteria but also considered how a potential candidate's expertise fits with other members of the Committee to ensure a balanced committee with expertise across the topic areas.
The Committee's work had 3 defining characteristics: the use of 3 approaches to examine the evidence, the creation of transparent protocols before the evidence review began, and the development of scientific review conclusion statements. The Committee answered each question on diet and health using 1 of 3 approaches: data analysis, food pattern modeling, and Nutrition Evidence Systematic Review (NESR) systematic reviews. Each of these approaches has its own rigorous, protocol-driven methodology and plays a unique, complementary role in examining the science.
Data analysis: The method of data analysis includes a collection of analyses that uses national data sets to describe and understand the current health and dietary intakes of Americans. These data help make the Dietary Guidelines practical, relevant, and achievable. The Committee conducted more than 150 analyses of federal data sets.
Food pattern modeling: Food pattern modeling shows how changes to the amounts or types of foods and beverages in a pattern may impact meeting nutrient needs across the US population. Several food pattern modeling analyses were completed including, for the first time, analyses of food patterns for children from 6 to 24 months old.
NESR systematic reviews: NESR systematic reviews are research projects that answer a question on diet and health by searching for, evaluating, and synthesizing all relevant, peer-reviewed studies within a specified period. More than 270 000 citations were screened, and nearly 1500 original research articles were included in 33 original systematic reviews.
The 2020 Committee created a protocol for each question, with support from USDA and HHS staff, before it examined any of the scientific evidence. This protocol served as a plan to examine research related to each of the questions (eg, inclusion/exclusion criteria for study design and date of publication).
The Committee looked across all of the conclusion statements—the totality of the scientific review—to develop overarching advice for USDA and HHS to consider as the Departments developed the 2020–2025 Dietary Guidelines. For example, the Committee reviewed 8 specific questions on dietary patterns related to health outcomes such as cardiovascular disease, risk of overweight and obesity, type 2 diabetes, bone health, cancer, neurocognitive health, and all-cause mortality. The Committee found consistent evidence that certain dietary components are associated with multiple outcomes and based their advice to the Department on this consistent evidence.
The updated process for developing the Dietary Guidelines for Americans increased transparency and public participation, as well as ensured that the scientific review conducted by the Committee would address federal nutrition policy and program needs and help manage resources.
The Committee's work culminated in the release of the Scientific Report of the 2020 Dietary Guidelines Advisory Committee posted at DietaryGuidelines.gov on July 15, 2020. 4 There were more than 10 000 downloads for this document in the first week.
As part of the Committee's scientific review, the report summarizes current intakes of foods, beverages, and nutrients across the life span. It is interesting to note that what Americans eat has not changed appreciably for the past decade. Throughout their life span, Americans overconsume calories, saturated fats, sodium, added sugars, and alcohol. In addition, they underconsume fruits, vegetables, dairy, and whole grains compared with recommendations. The report also identifies nutrients or food components of public health concern due to underconsumption, where inadequacy of those nutrients is linked to specific health conditions. This is based on intake data and evidence through biochemical indices or functional status indicators. These nutrients or food components are of public health concern for all Americans: vitamin D, calcium, dietary fiber, and potassium.
The Committee reviewed evidence on the relationship between nutrition and health outcomes for the entire life span from infants to older adults and including pregnancy and lactation. The report emphasized the importance of consuming a healthy dietary pattern at every life stage to meet nutrient needs, maintain proper growth or energy balance, and reduce the risk of chronic disease.
The evidence reviewed by the Committee reinforces the importance of nutrition for women before and during pregnancy and lactation for optimal maternal and fetal outcomes. The Committee concluded that consuming a healthy dietary pattern before and/or during pregnancy may modestly reduce the risk of gestational diabetes, hypertensive disorders of pregnancy, excessive gestational weight gain, and preterm birth. For both pregnancy and lactation, the Committee's review suggested that seafood choices are important components of a healthy dietary pattern along with other core components, including vegetables, fruits, legumes, whole grains, low-fat or nonfat dairy, lean meat and poultry, nuts, and unsaturated vegetable oils.
On the basis of intake data, biomarker data, and clinical outcomes, women who are pregnant or lactating have similar food components of public health concern (vitamin D, calcium, dietary fiber, and potassium) as the rest of the population, but iron and folate/folic acid status is also of particular importance during pregnancy. Without supplements and careful food choices, women who are pregnant are at a high risk for inadequacy for these nutrients. The Committee determined that, during pregnancy and lactation, consuming a healthy dietary pattern (Healthy US-Style, Healthy Vegetarian, and Healthy Mediterranean-Style) would meet most nutrient needs. During pregnancy, women should also specifically incorporate foods rich in iron, folate, choline, and vitamins D and E. During lactation, foods rich in choline, and vitamins A, D, and E are important to incorporate. Because iron needs are lower during lactation compared with pregnancy, research supports the discontinuation of prenatal high–iron-dose supplements during lactation unless medically indicated.
The Committee's review also indicated that the avoidance of potentially allergenic foods during pregnancy and lactation is not recommended, unless medically necessary to protect the mother's health. The Committee recommended that women follow existing guidance on alcohol and caffeine consumption during pregnancy and lactation and emphasized that maintaining a healthy prepregnancy weight, achieving appropriate weight gain during lactation, and returning to a healthy weight during the postpartum period are essential.
The Committee encouraged exclusive breastfeeding, ideally for the first 6 months of life, with continued breastfeeding through the first year of life or longer as desired by the mother and infant. On the basis of the evidence reviewed, the Committee concluded that complementary foods and beverages (CFB) should not be introduced before 4 months old. The Committee found that introduction at 4 to 5 months old as compared with 6 months old does not offer long-term advantages or disadvantages. It recommended that CFB include foods that are rich in iron and zinc, either intrinsically (eg, meats) or due to fortification (eg, iron-fortified infant cereal), particularly from the age of 6 to 12 months among breastfed infants. Complementary foods and beverages should also contain adequate amounts of polyunsaturated fatty acids. The Committee concluded that, once CFB are introduced, adding peanut and egg in developmentally appropriate forms in the first year of life (6-12 months old) may reduce the risk of food allergy to these foods. The Committee found no evidence that avoiding other potentially allergenic foods (fish, shellfish, cow milk products, tree nuts, seeds, wheat, and soy) in the first year of life is beneficial with regard to preventing food allergies or other atopic diseases.
On the basis of its evidence review, the Committee concluded that routine iron supplementation of all breastfed infants may not be advisable, although it acknowledged that screening for iron deficiency using appropriate biomarkers, such as serum ferritin, may be challenging because it is not as simple as measuring hemoglobin. After 6 months, other sources of iron, such as iron-rich or iron-fortified complementary foods, can be provided, so iron supplementation is generally not needed. The Committee also concluded that there is no basis for recommending vitamin D supplementation higher than 400 IU per day during infancy.
The Committee conducted food pattern modeling to determine whether USDA food patterns could be established for infants and toddlers ages 6 to 24 months. 5 A food pattern for infants 6 to 12 months old could not be established because of challenges with uncertainty about nutrient requirements and difficulty in meeting the Recommended Dietary Allowance for iron through CFB. However, combinations of CFB were described by the Committee that meet most nutrient requirements while infants are still consuming different proportions of human milk or infant formula. The Committee recommended providing infants and toddlers with a variety of animal-source foods (meat, poultry, seafood, eggs, and dairy), fruits and vegetables, nuts and seeds, and whole-grain products, beginning at 6 to 12 months old and continuing thereafter. For toddlers 12 to 24 months old whose diets do not include meat, poultry, or seafood, the Committee advised providing eggs and dairy products on a regular basis, along with soy products and nuts or seeds, fruits, vegetables, grains, and oils. The Committee also recommended not providing foods and beverages with added sugars, such as sugar-sweetened beverages, to children younger than 2 months because energy from added sugars is likely to displace energy from nutrient-dense foods and because some evidence suggests a relationship with subsequent risk of child overweight. In addition, because food preferences begin at an early age, it is important to encourage regular consumption of nutrient-dense foods and beverages.
The Committee's extensive evidence review found that dietary patterns higher in vegetables, fruits, legumes, whole grains, low-fat or nonfat dairy, lean meat and poultry, seafood, nuts, and unsaturated vegetable oils, and low in red and processed meats, sugar-sweetened foods and beverages, and refined grains are associated with a range of beneficial health outcomes. Beneficial outcomes associated with these healthy dietary patterns include reduced risk of all-cause mortality, cardiovascular disease, type 2 diabetes, overweight and obesity, bone health, and several cancers. These core dietary pattern elements are appropriate across the life span from children to older adults.
On the basis of its review of the evidence for a relationship between types of dietary fats consumed and cardiovascular disease risk, the Committee advised limiting intake of saturated fats to less than 10% of energy per day by replacing them with unsaturated fats and keeping dietary cholesterol intake as low as possible. The Committee also recommended 2 or more servings of cooked seafood per week for individuals 2 years and older to ensure intake of key nutrients and as part of an overall healthy dietary pattern. Serving sizes vary based on age and seafood choices should emphasize species higher in omega-3 fatty acids and low in methylmercury, following federal and local fish and seafood advisories. 6 For those who do not consume seafood, the Committee concluded that regular intake of other foods high in omega-3 fatty acids, such as flaxseeds, walnuts, soy oil, algae, and eggs that contain omega-3 fatty acids, is appropriate.
The Committee also examined the relationship between beverage consumption and weight status. It concluded that nutrient-rich beverages (eg, fat-free or low-fat milk, 100% juice) contribute substantively to food group and nutrient intakes but that it is important to be mindful of their contribution to total energy intake. Because sugar-sweetened beverages contribute substantial energy to the diet and contribute very little toward meeting food group and nutrient recommendations, the Committee encouraged only limited intake of these beverages. The Committee acknowledged that low- and no-calorie sweetened beverages may be a useful aid in weight management in adults, but that evidence was limited. The Committee emphasized that the role beverages play in diet quality and energy balance varies across the life span and that recommendations should be tailored appropriately.
On the basis of its review of the evidence regarding alcohol consumption, the Committee concluded that, for those who do not drink, it is not wise to begin drinking alcohol or purposefully continue to drink alcohol for health reasons. For adults who do drink alcohol, the Committee's review indicated that, at all levels of consumption, drinking less is generally better for health than drinking more. The Committee recommended that adults limit alcohol intake to no more than 1 drink per day for both women and men for better health.
The Committee suggested that, for adults and for children 2 years and older, a recommendation of less than 6% of energy from added sugars is more consistent with a dietary pattern that is both nutritionally and calorically appropriate, than is a pattern with less than 10% of energy from added sugars, as was recommended in past editions of the Dietary Guidelines. The Committee's advice was based on food pattern modeling and the evidence on health impacts of added sugars intake.
Finally, the Committee continued to recommend established USDA Food Patterns: Healthy U.S.-Style, Healthy Vegetarian Style, and Healthy Mediterranean-Style. The core components of all 3 USDA Food Patterns include fruits, vegetables, legumes, whole grains, nuts, and seeds; protein and fats from nutrient-rich food sources; and limited amounts of added sugars, saturated fat, and sodium.
The Scientific Report of the 2020 Dietary Guidelines Advisory Committee summarizes a wealth of nutrition research completed by nutrition investigators throughout the world and served as the scientific basis for the Dietary Guidelines for Americans, 2020–2025.
The public was encouraged to provide input at various times throughout the process of the development of the Dietary Guidelines. Before the 2020 Advisory Committee was established, the public was invited to provide comments on the topics and scientific questions to be examined by the Committee. The public was also able to nominate candidates for Committee membership. For the first time in the Committee process, draft protocols were posted online for public comments to the Committee before they were finalized. The public was also invited to submit written comments and to provide oral testimony to the Committee during the time that the Committee was reviewing the evidence. In addition, after the Committee's scientific report was submitted to the Departments, the public was able to give written comments, for a time, as well as oral comments on the report to federal staff at a public meeting. The Committee received more than 62 000 written public comments from March 12, 2019, to June 10, 2020, which consisted of approximately 4000 unique comments.
Each edition of the Dietary Guidelines builds on the preceding edition, with the scientific justification for revisions informed by the Advisory Committee's Scientific Report, consultation with subject matter experts within federal agencies, and consideration of comments from these agencies and the public. The USDA and HHS received 38 000 comments on the Advisory Committee's Scientific Report, and these were considered in the development of the Dietary Guidelines.
Development of the Dietary Guidelines involves a step-by-step process of writing, review, and revision supported by a writing team of federal staff from USDA and HHS. The writing team included federal nutrition scientists with expertise in the Dietary Guidelines and related research and programs as well as specialists with expertise in communicating nutrition information. It was written with the fundamental understanding that it must represent the totality of the evidence, address the needs of federal programs, work to reduce unintended consequences, follow best practices, and use plain language. The draft Dietary Guidelines then underwent several rounds of review and revisions by all agencies with nutrition policies and programs across the USDA and HHS, as well as external experts. The review finally culminated with the Secretaries of USDA and HHS. After approval by the Secretaries, the Departments released the Dietary Guidelines to federal agencies and the public for implementation across programs and through educational activities.
The Dietary Guidelines for Americans, 2020–2025 includes nearly all of the science-based recommendations of the 2020 Dietary Guidelines Advisory Committee, including new dietary advice for infants and toddlers. The Dietary Guidelines includes part, but not all, of the Committee's advice on added sugars and alcohol. The new edition emphasizes the importance of limiting intakes of added sugars and alcoholic beverages but does not include the changes to quantitative limits recommended by the Committee. The evidence that the Committee reviewed supports the need to continue to limit intakes of added sugars and alcoholic beverages to promote health and prevent diseases. However, there was not a preponderance of evidence in the Committee's review of studies since the 2015–2020 edition to substantiate changes to the quantitative limits for either added sugars or alcohol. The Dietary Guidelines underscores the importance of limiting added sugars and alcohol intake and carries forward the quantitative limits from the 2015–2020 edition. The USDA and HHS encourage more research on the relationship between added sugars and alcoholic beverages and health and will continue to monitor the evidence on these topics.
Chapter 1 of the Dietary Guidelines discusses 4 overarching guidelines (Figure (Figure3) 3 ) that serve to promote healthy dietary patterns across the life span and are supported by key recommendations that provide more specific guidance. These core recommendations are consistent with the 2015–2020 Dietary Guidelines.
