Public comment by the Nutrition Coalition to USDA-HHS on the Scientific Report for the next edition of the Dietary Guidelines.
To: The Secretaries of the U.S. Departments of Agriculture and Health and Human Services
Re: 2025 Scientific Report by the Dietary Guidelines Advisory Committee
Date: February 10, 2025
The Nutrition Coalition is grateful to participate in the public comment process for the 2025 US Dietary Guidelines for Americans. We suggest the following actions by the U.S. Departments of Agriculture and Health and Human Services (USDA-HHS).
We recommend not accepting any of the new proposals in the Scientific Report of the Dietary Guidelines Advisory Committee(“Report”) for the following reasons:
Use of an unvalidated, non-rigorous methodology for reviewing the science
The methodologies used to create the Report are not recognized, or validated; They do not comply with internationally recognized standards in the field. The following documents support this statement:
A two-part report by the National Academies of Sciences, Engineering, and Medicine (NASEM) in 2017[1,2] found that the methodological approaches for evaluating the science in the U.S. Dietary Guidelines “require increased rigor to better meet current standards of practice.” The NASEM said the USDA methodology currently “falls short of meeting the best practices for conducting systematic reviews,” and “To develop a trustworthy DGA, the process needs to be redesigned.”[3]
This report was mandated by Congress, with a $1 million allocation.
The NASEM made 11 recommendations to the USDA. [4]
The NASEM followed up in two reports published in 2022 and 2023 [5,6] which found that the USDA had not fully complied with any of the NASEM’s recommendations.
“The proposed analytic and methodologic improvements to the Dietary Guidelines process has largely not yet been achieved” (NASEM, 2023).
The Nutrition Coalition’s analysis of these reports concluding the same can be found here. [7]
A recent paper in the esteemed American Journal of Clinical Nutrition authored by an international team of top methodologists found that the USDA systematic reviews to be “suboptimal” and of “critically low quality.”[8]
Among the paper’s many findings were that the USDA scientific literature search could not be replicated by a large margin of error. An attempt by the AJCN authors to replicate the searches used for the systematic reviews of the Dietary Patterns and the outcomes obesity, type 2 diabetes, and heart disease yielded three times more studies than those found by the USDA (10,201 papers vs. 3,550 by USDA).
Replication is a fundamental principle of reliable science, yet the USDA systematic reviews on the Dietary Patterns failed the first step of the replication process (i.e., the literature search).
Use of computer modeling for the 2025 Report
No guidelines process has ever before employed computer modeling of diets. Modeling is a very low-quality form of evidence since it involves many (potentially false) assumptions and does not rely on empirical data. We question why the USDA used computer modeling when there is an abundance of far more rigorous data available from controlled clinical trials.
Serious problems with the USDA computer modeling include:[9]
No distinctions were made between various kinds of fruits and vegetables. For instance, the model did not distinguish between a tomato (< 5 grams of carbohydrates per serving) and a sweet potato (27 carbs); Both are part of the “red and yellow vegetables category”
The model did not control for portion size;
The model did not include “mixed dishes,” such as lasagna and hamburgers, although these are a major source of calories for Americans;
A modeling exercise on the “low-carbohydrate” diet removed more than half of the calories as carbohydrates but, curiously, did not replace those calories with any other foods, resulting in a predictable, precipitous drop in nutritional adequacy. This approach is non-sensical.
This approach also ignores the large quantity of randomized, controlled clinical trials on low-carbohydrate diets, which are a far more rigorous source of evidence (These trials, dating back to the early 2000s, have never been reviewed by any Dietary Guidelines Advisory Committee.)
The model made hundreds of assumptions, yet outsiders cannot examine these assumptions since there appears to be no public access to the modeling data. This process is a black box that flies in the face of the principle of transparency.
Lack of transparency in the Guidelines process
The USDA did not disclose conflicts of interest (COI) on the Dietary Guidelines Advisory Committee, as the NASEM had recommended.1 Disclosure of COI is also the international standard for guidelines committees and has been endorsed by the Institute of Medicine.
The 2025 DGAC voluntarily disclosed its COI but in an aggregated way, without revealing individual ties. To our knowledge, this kind of non-specific disclosure has never before occurred. Failing to identify the person linked to the particular conflict largely invalidates disclosure. We need to know who is tied to which company. This knowledge is especially important, because committee members serve on different DGAC subcommittees, for which their COIs are directly relevant.
Senator Chuck Grassley tried to halt the Dietary Guidelines process until proper disclosure of COI was made, but he was unsuccessful.[10]
Lack of rigorous evidence for the USDA-HHS Dietary Patterns
The USDA-HHS Dietary Patterns are based on a “minuscule quantity” of rigorous data, according to a peer-reviewed and much-scrutinized cover story in the BMJ (formerly the British Medical Journal), one of the world’s oldest and most prestigious scientific journals.[11] The analysis in this article, by Dr. Nina Teicholz, included a review of all the clinical trials cited by the USDA to support its claims that the Dietary Patterns could prevent obesity, type 2 diabetes, or heart disease. The quantity of clinical trials cited by USDA-HHS to support these claims was minimal.
Today, the situation is no different. An analysis by Dr. Teicholz on the three USDA systematic reviews on the Dietary Patterns and obesity, type 2 diabetes, and heart disease for the 2025 Report found the following:
These reviews cited trials as support for the claims that the Dietary Patterns prevent disease, but:
Many trials cited were found not to have “statistically significant”1 results on health outcomes;
Many “trials” were incorrectly listed as clinical trials but were instead follow-up observational studies to clinical trials. Observational data is a far lower-quality form of evidence.
0% (0/9) of the trials supported the claim that the USDA-HHS Dietary Patterns could prevent heart disease
29% (7/24) of the trials supported the claim that the USDA-HHS Dietary Patterns could prevent obesity
8% (1/13) of the trials supported the claim that the USDA-HHS Dietary Patterns could prevent type 2 diabetes
In all, just 17% (17/46) of trials supported the claim that the USDA-HHS Dietary Patterns could prevent any of these diseases.
Harm to human health by the proposal to reduce meat, poultry, and eggs and replace them with peas, beans, and lentils in the “US-Style” Dietary Pattern
The proposal to reduce meat, poultry, and eggs by 3 ½ - 4 ounce-equivalents per week for people eating at least 2,200 calories is highly problematic.
First, this recommendation is not based on rigorous evidence. This recommendation arises from computer modeling and systematic reviews on the Dietary Patterns, both extremely flawed (see above).
Second, this proposal will harm human health by the following mechanisms:
Peas, beans, and lentils provide an incomplete and less digestible source of protein compared to animal foods. Complete, digestible sources of protein are almost entirely from animal foods. Only complete proteins are uniquely able to build muscle and perform many other essential functions in the body. These facts are well-established in the scientific literature. We have cited some references in this blog post on “The Erosion of Protein in the Dietary Guidelines.”[12]
Peas, beans, and lentils deliver a high load of starch, i.e., carbohydrates, which cannot be tolerated by people with metabolic (chronic) diseases such as type 2 diabetes. The excessive starch from these plant sources of protein will exacerbate these and other diseases. By contrast, meat, poultry, and eggs contain no carbohydrates and, for this reason, are a far more healthy source of protein.
Peas, beans, and lentils are relatively poor in nutrients compared to meat, poultry, and eggs. The guidelines already fail to meet nutrient goals for vitamins D and E, folate, choline, and iron. According to the 2025 DGAC final meeting, the shift to more peas, beans, and lentils would lead to further shortfalls in vitamins D and E.
Harm to human health by the proposal to reduce red and processed meat
This recommendation is based on extremely weak evidence and is contradicted by strong evidence to the contrary. Further, reducing red and processed meat will harm human health.
This recommendation is not based on rigorous evidence. This recommendation arises from computer modeling and systematic reviews of the Dietary Patterns, both extremely flawed (see above).
Further, this recommendation is contradicted by the highest-quality systematic reviews ever conducted on this topic, conducted according to the world-renowned “GRADE” methodology (Grading of Recommendations, Assessment, Development, and Evaluation) and published in the Annals of Internal Medicine. These papers found that the relationships between red/processed meat and disease (cancer, type 2 diabetes, and heart disease) were supported by only a very small amount of “low” to “very low” quality evidence. The conclusion must be that there is insufficient data to recommend reductions in red or processed meat. The Annals papers are the most rigorous reviews on red/processed meat.[13]
Red meat is a nutrient-dense food that provides several essential nutrients often lacking in the typical American diet. Red meat is a highly bioavailable protein that is a rich source of iron, zinc, and vitamin B12. These nutrients can be limited or absent in many plant-source foods as well as in some animal-source foods. Red meat's micronutrient profile is especially valuable for young children and women of reproductive age, including pregnant women. In addition, the protein density of red meat is beneficial for individuals managing obesity and older adults at risk of sarcopenia. These points are documented in the paper “Considering the Nutritional Benefits and Health Implications of Red Meat in the Era of Meatless Initiatives,” published in Nutrients this year.[14]
Further, an analysis by Dr. Teicholz found that the evidence to show that red/processed meat causes cancer is minimal and that the International Agency for Cancer (IARC) panel convened to review this topic in 2015 was highly biased. Teicholz found that before joining the IARC working group, fully 77% [15] of the 22 members had published multiple papers endeavoring to show that meat causes cancer, and six had been doing this research for 20-30 years. Teicholz also found that the science employed was weak and that contradictory findings were both suppressed and ignored.
Harm to human health by further reducing the nutritional adequacy of the Dietary Patterns
It is a disquieting fact that the U.S. Dietary Guidelines, even if followed perfectly, fail to deliver all the essential nutrients needed for growth, reproduction, and healthy life. The guidelines should, at a minimum, provide for our basic nutrient needs.
The current guidelines fall short of meeting the goals for vitamins D and E, folate, choline, and iron. The 2025 Report recommendations would increase these shortfalls.
We also recommend the following changes to the 2025 Dietary Guidelines.
Eliminate the recommended 3 servings/day of refined grains in the Dietary Patterns
The continued inclusion of refined grains in the guidelines is hard to justify. These highly processed, refined grains are known to spike blood sugar and, over time, provoke the condition of insulin resistance, which is the root cause of obesity, type 2 diabetes, and heart disease.
The continued inclusion of refined grains was a controversial subject in the final meeting of the DGAC. DGAC Chair Sarah Booth responded to criticism by stating, “If we reduced refined grains, there would be nutritional inadequacies.” Booth is referring to the fact that only refined—not whole—grains are enriched and fortified with vitamins and minerals. These nutrients are crucial for helping the guidelines reach even subpar nutritional adequacy. Removing refined grains will therefore increase these nutrient shortfalls.
However, there is a better solution. We suggest recommending that Americans get their nutrients from the whole, natural foods in which these vitamins and minerals naturally occur, i.e., meat, poultry, eggs, dairy, fish, and shellfish. We should eliminate refined grains-- which are a known health harm—and replace them with whole foods. This is a common-sense argument.
Clarify the advice on dietary cholesterol
The public is rightfully confused about dietary cholesterol by the fact that the USDA-HHS Dietary Patterns are said to be “lower in cholesterol”. At the same time, the guidelines have removed its numeric cap on cholesterol. The USDA scientific reviews in both 2015 and 2020 concluded that there was no relationship between dietary and blood cholesterol:
The systematic review for the 2015 guidelines concluded that there is “no appreciable relationship between consumption of dietary cholesterol and serum cholesterol.”[16]
The review for the 2020 guidelines concluded that there was “insufficient evidence” to link dietary cholesterol with blood cholesterol.
The language saying that Dietary Patterns are typically “lower in cholesterol” is derived exclusively from observational (epidemiological) studies, which are a weak source of evidence.
This conflicting advice on dietary cholesterol was documented in a paper published in PNAS Nexus, a publication of the NASEM, whose authors included several former members of previous Dietary Guidelines Advisory Committees.[17]
In our view, the Dietary Guidelines should reflect the conclusions of its systematic reviews, which state that there should be no advice to reduce dietary cholesterol.
Clarify the advice on total fat
The Dietary Guidelines no longer uses “low-fat” language and omits any mention of limiting total fat. However, the USDA formulations for its Dietary Patterns are still, de facto, low in fat:
The range of 31-32% fat as a percent of total calories is solidly within the range of the “low-fat” diet studied in the scientific literature. This fact is also documented in the aforementioned PNAS Nexus paper.
We recommend formulating the Dietary Patterns to be higher in fat. A wealth of scientific literature shows that diets at least 55% fat (and lower in carbohydrates) are more effective for reversing chronic diseases, including obesity, type 2 diabetes, and heart disease.[18]
If this change is not possible, we suggest that the Dietary Guidelines make clear that its recommended Dietary Patterns are still de facto low in fat and that the USDA-HHS recognize this topic urgently needs to be revisited.
We are grateful for your attention in reading these comments. We look forward to seeing a U.S. Dietary Guidelines for Americans that can prevent disease and restore good health to the public.
Respectfully,
Nina Teicholz
Chair, The Nutrition Coalition
Nutritioncoalition.us
[3] Summary of findings can be found here: https://www.nutritioncoalition.us/the-process-of-drafting-the-guidelines-needs-reform
[4] The USDA co-issues the U.S. Dietary Guidelines for Americans with the U.S Department of Health and Human Services, but the office that conducts the science reviews and administers the guidelines is housed at USDA.
[8] https://www.sciencedirect.com/science/article/pii/S0002916524008207?via%3Dihub
[9] These details were revealed in the final meeting of the 2025 Dietary Guidelines Advisory Committee.
[11] Teicholz N. The scientific report guiding the US dietary guidelines: is it scientific? BMJ 2015; 351 :h4962 doi:10.1136/bmj.h4962
[12] https://www.nutritioncoalition.us/news/erosion-of-protein-in-us-dietary-guidelines
[13] https://pubmed.ncbi.nlm.nih.gov/?term=Zeraatkar+D+meat+cancer&sort=pubdate&size=200
[14] https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1525011/full
[15] https://unsettledscience.substack.com/p/do-red-and-processed-meats-cause
[16] Report by the 2015 Dietary Guidelines Advisory Committee, USDA-HHS, 2015.
[17] Cheryl Achterberg, Arne Astrup, Dennis M Bier, Janet C King, Ronald M Krauss, Nina Teicholz, Jeff S Volek, An analysis of the recent US dietary guidelines process in light of its federal mandate and a National Academies report, PNAS Nexus, Volume 1, Issue 3, July 2022, pgac107, https://doi.org/10.1093/pnasnexus/pgac107
[18] Volek, J.S.; Phinney, S.D.; Krauss, R.M.; Johnson, R.J.; Saslow, L.R.; Gower, B.; Yancy, W.S., Jr.; King, J.C.; Hecht, F.M.; Teicholz, N.; Bistrian, B.R.; Hamdy, O. Alternative Dietary Patterns for Americans: Low-Carbohydrate Diets. Nutrients 2021, 13, 3299. https://doi.org/10.3390/nu13103299