Dear Members of the 2025 Dietary Guidelines Advisory Committee,

I write to urge the Dietary Guidelines Advisory Committee (DGAC) to add a question about the science on low-carbohydrate diets to the list of scientific questions to review for the 2025-2030 Dietary Guidelines for Americans.

I want to ensure that the DGAC is aware that the vast majority of submissions during the public comment period regarding these scientific questions, from April 14, 2022 through May 16, 2022, asked for a review of the science on these diets, in relation to various health outcomes.

Agri-Pulse reported that some 700 of 916 comments, or 77% of the total, demanded that the U.S. Departments of Agriculture and Health and Human Services (USDA-HHS) consider this science. This topic was omitted from a draft list of questions published by USDA-HHS in March. We respectfully ask that you respond to these public comments and not ignore this important nutritional approach for the next iteration of the guidelines.

Specifically, we request that you review low-carbohydrate diets and the health outcomes of weight loss and blood sugar control. The latter, as undoubtedly you know, is a crucial factor for combatting pre-diabetes and diabetes as well as cardiovascular risk. A low-carbohydrate diet should be defined exclusively by the carbohydrate content, not the other macronutrients in the diet. An erroneous definition of the diet will lead to the unnecessary exclusion of studies, as occurred during the last iteration of the guidelines, when the scientific review could not find a single low-carbohydrate study. We attach a paper in Nutrients whose authors include former members of previous DGACs as well as the leading researchers in the field of low carbohydrate diets, to provide guidance on definitions and an overview of the research to date. ¹

The public comments asking for a review of this diet came from a mix of scientists, medical professionals and concerned citizens. Individuals wrote in their own words, often with personal stories; these were not “robo” comments. One group, the Society for Metabolic Health Practitioners, submitted a single comment that included 475 signatures by doctors and other practitioners, bringing the total individual commenters on this topic to nearly 1200.

The public outcry expressed by these comments is supported by a growing scientific literature showing low-carbohydrate diets to be safe and effective for people with diet-related diseases. Given this public plea, backed by at least 100 clinical trials, we wanted to ensure that the DGAC respects this public contribution by agreeing to explore questions regarding the science of low-carbohydrate diets as part of the review process for the next edition of the Dietary Guidelines.

Leading health organizations have acknowledged the strong evidence for a low-carbohydrate diet and we urge the Committee to follow their lead.

The American Diabetes Association (ADA) has deemed the low-carbohydrate diet a “standard of care” ² and recognized it as having, “the most evidence for improving glycemia [blood sugar control],” a vital tool for patients with diabetes or pre-diabetes. ³ The low-carbohydrate diet has also been acknowledged by the American Heart Association (AHA) as leading to, “more weight loss and use of fewer diabetes medications in individuals with diabetes.” ⁴

At a time of soaring rates of diet-related diseases, which disproportionately affect historically marginalized people, we must use all the tools at our disposal to lower the social, personal and financial costs of these illnesses. The U.S. guidelines are arguably our most important tool to do so. As the public comments implore, we must remain open to exploring dietary options that could help the millions of Americans who suffer from one or more diet-related diseases.

Public comment periods reflect our shared commitment to the principles of openness and transparency in the democratic process. We believe it is our duty to honor both the process and the public, by recognizing and responding to their collective call for addressing the science on low-carbohydrate diets. By acknowledging their concerns with a thorough review of the science, we will demonstrate that the public’s voice does matter.

Thank you in advance for your consideration for adding a question about the science of low carbohydrate diets to the list of scientific questions for review in the next iteration of the dietary guidelines.

¹ 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

² A Consensus Report by the American Diabetes Association (ADA) and the European Association for the Study of Diabetes (EASD). Diabetes Care 1 December 2018; 41 (12): 2669–2701. https://doi.org/10.2337/dci18-0033.

³ Nutrition Therapy for Adults With Diabetes or Prediabetes: A Consensus Report. Diabetes Care 1 May 2019; 42 (5): 731–754. https://doi.org/10.2337/dci19-0014

⁴ Joseph JJ, Deedwania P, Acharya T, Aguilar D, Bhatt DL, Chyun DA, Di Palo KE, Golden SH, Sperling LS; on behalf of the American Heart Association Diabetes Committee of the Council on Lifestyle and Cardiometabolic Health; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Clinical Cardiology; and Council on Hypertension. Comprehensive management of cardiovascular risk factors for adults with type 2 diabetes: a scientific statement from the American Heart Association. Circulation. 2022;145:e722–e759. doi: 10.1161/CIR.0000000000001040