The 2025 Dietary Guidelines Advisory Committee (DGAC,Committee) conducted 28 systematic reviews with support from USDA’s Nutrition Evidence Systematic Review (NESR) branch within the Food and Nutrition Service, Center for Nutrition Policy and Promotion. All of the Committee’s systematic reviews underwent external peer review by nutrition scientists in a process coordinated by staff from the National Institutes of Health (NIH). As a research center, NIH has access to nutrition scientists and networks with professional organizations to support peer review. Additionally, while within HHS, the NIH staff coordinating the peer review were separate from staff supporting the Committee’s work.
Peer Review Process for Systematic Reviews Conducted by the 2025 DGAC
NIH staff identified potential peer reviewers through outreach to a variety of professional organizations to select academic reviewers from U.S. colleges and universities with a doctorate degree, including medical doctors, and expertise specific to the questions being reviewed. All peer reviewers were external to the Dietary Guidelines for Americans (Dietary Guidelines) process; therefore, current Committee members and federal staff who supported the Committee, or who were involved in the development of the Dietary Guidelines, were not eligible to serve as peer reviewers. Federal scientists who were not involved in the development of the Dietary Guidelines were eligible to serve as peer reviewers, as were past members of Dietary Guidelines Advisory Committees, as long as they were not serving on the 2025 Committee.
NIH staff assigned each systematic review to a minimum of 2 peer reviewers. The peer review process was anonymous and confidential in that the peer reviewers were not identified to the Committee members or NESR staff, and in turn, the reviewers were asked not to share or discuss reviews with anyone. Peer reviewers were made aware that per USDA, FNS agency policy, all peer reviewer comments would be summarized and made public, but comments would not be attributed to a specific reviewer. The reviewers were welcome to provide feedback on any aspect of the systematic reviews, but were specifically asked to evaluate the following sections of the systematic reviews:
- They were asked to determine if the “Description of the Evidence,” “Synthesis of Evidence,” and “Assessment of the Evidence” sections were clearly written and organized so that they provide transparency to the body of evidence reviewed.
- They were asked if the Conclusion Statement(s) and Grade(s) were supported by the body of evidence reviewed.
- They were asked to evaluate the Research Recommendations and suggest any additional research recommendations be made to encourage future research to inform agency programs, guidance, and/or policy.
Each reviewer was instructed to submit their comments in written form. In addition, reviewers were informed that the agencies would be required to make available to the public the written charge to the peer reviewers; the peer reviewers’ names, affiliations, and expertise; and a summary of the comments from peer reviewers, but that comments would not be attributed to a specific named peer reviewer.
Summary of Peer Review Comments on the Systematic Reviews Conducted by the 2025 DGAC
Twenty-five nutrition experts served as peer reviewers across the 28 systematic reviews conducted by the Committee. The comments received from these peer reviewers were generally positive, as peer reviewers commonly complimented the methods, writing, and transparency of the systematic reviews. In a few instances, outlined below, peer reviewers suggested that the Committee reconsider the evidence and/or the conclusion statement(s) and grade(s). However, most of the feedback was editorial in nature. Many of these editorial comments included suggestions to clarify key concepts, definitions, or methods, and/or provide additional information on the articles included in the systematic review. Where necessary, changes were made to the systematic review to address these comments.
Peer reviewers commonly expressed agreement with the conclusion statement(s) and grade(s) assigned to each systematic review question, as well as research recommendations made, with a few exceptions that are described below:
- Peer reviewer comments on conclusion statements and grades
Based on peer reviewer feedback, one conclusion statement and grade for the systematic review question was revised by the Committee, for the review examining the following question: “What is the relationship between frequency of meals and/or snacking and energy intake?” The Committee re-evaluated the evidence, taking into consideration the peer reviewer comments, and determined that a change to the conclusion statement and grade for breakfast and energy intake in adults was warranted:
- Draft conclusion statement and grade: “Breakfast consumption compared to no breakfast consumption in adults does not decrease total energy intake. This conclusion statement is based on evidence graded as limited. (Grade: Limited)”
- Final conclusion statement and grade: “A conclusion statement cannot be drawn about the relationship between breakfast consumption in adults and total daily energy intake because of substantial concerns with consistency and generalizability in the body of evidence. (Grade: Grade Not Assignable)”
Several systematic reviews also received comments from peer reviewers that suggested the Committee reevaluate the evidence and/or reconsider the conclusion statement(s) and grade(s), including:
- What is the relationship between complementary feeding and growth, body composition, and risk of obesity?
- What is the relationship between consumption of dietary patterns with varying amounts of ultra-processed foods and growth, body composition, and risk of obesity?
- What is the relationship between dietary patterns consumed and risk of cognitive decline, dementia, Alzheimer's disease, and mild cognitive impairment?
- What is the relationship between dietary patterns consumed during pregnancy and gestational age at birth?
The Committee considered the peer reviewer feedback and the evidence reviewed but opted to maintain their original draft conclusion statement(s) and grade(s). In these cases, the Committee provided a rationale for their decisions in responses provided to the peer reviewers, and, where appropriate, made revisions to the systematic review to more clearly provide the scientific rationale for the final conclusion statements and grades. In some cases, they also added research recommendations to the systematic review to suggest research that could strengthen the evidence used in future iterations of the Dietary Guidelines.
- Peer reviewer comments on research recommendations
Throughout the systematic review process, the Committee identifies research gaps and methodological limitations that are used to develop research recommendations that describe the research, data, and methodological advances that are needed to strengthen the body of evidence on a particular topic. The Committee received several comments from peer reviewers regarding the need for additional research recommendations. In the case that (a) suggested research recommendation(s) was not encompassed elsewhere in the systematic review, these recommendations were added per the reviewers’ feedback.
- Peer reviewer comments on the systematic review methodology
There were a few instances where a peer reviewer asked for additional clarification on the methodology used to conduct a systematic review, such as on the grading criteria and rationale, choice of key confounders identified in the analytic framework, risk of bias assessments, and synthesis methods. Peer reviewers were provided with answers to their questions and were also directed to the NESR Methodology Manual for more details regarding the NESR methodology.
NESR Systematic Review Peer Reviewers
The following individuals served as peer reviewers for the 2025 Dietary Guidelines Advisory Committee’s systematic reviews and were identified by NIH to have expertise specific to the topics addressed in the Committee’s reviews.
Mary Story, PhD, RD
Duke University
Regan Bailey, PhD, MPH, RD
Texas A&M University
Sharon Donovan, PhD, RD
University of Illinois, Urbana-Champaign
Teresa Davis, PhD, MS
Baylor College of Medicine
Rachel Novotny, PhD, RDN, LD
University of Hawai’i
Jamie Stang, PhD, MPH, RD
University of Minnesota
Mark R. Corkins, MD, CNSC, FASPEN, AGAF, FAAP
University of Tennessee Health Science Center
Kelly Martin DCN, RDN, CDN
State University of New York at Oneonta
Margaret O. Murphy, PhD, RD, LD
University of Kentucky
Lauren Coheley Spain, PhD, RDN, LD, CDE, FAND, E-RYT
Texas A&M University
Kristi M. Crowe-White, PhD, RD
University of Alabama
Christine Ferguson, PhD, RD, CSG
University of Alabama at Birmingham
Kim S. Stote, PhD, MPH, RDN, CDN
State University of New York, Empire State University
Jennifer T. Smilowitz, PhD
University of California, Davis
Kathleen J. Melanson, PhD, RD, LDN
University of Rhode Island
Marybeth Mitcham, PhD, MPH
George Mason University
Douglas Kalman, PhD, RD
Nova Southeastern University
Sibylle Kranz, PhD, RND, FTOS
University of Virginia
Sarah Ardanuy Johnson, PhD, RDN
Colorado State University
Lauren E. O’Connor, PhD, MPH
Texas A&M University
Virginia Uhley, PhD, RD
Oakland University
Dariush Mozaffarian, MD, DrPH
Tufts University
Emily Johnston, PhD, MPH, RDN, CDCES
New York University Grossman School of Medicine
Ligia Reyes, PhD, MPH
Pennsylvania State University