Why Nutrition Experts Are Questioning How America's New Dietary Guidelines Were Made

The American Society for Nutrition (ASN) is sounding the alarm about a significant change in how the nation's most influential dietary recommendations were developed, warning that departing from established scientific review processes could undermine public trust in nutrition guidance. The organization supports the broad eating patterns in the newly released 2025-2030 Dietary Guidelines for Americans but has serious concerns about the scientific review process behind them.

What Changed in the Scientific Review Process?

For the first time in the guidelines' history, federal agencies introduced a separate "Scientific Foundation for the Dietary Guidelines for Americans" report instead of relying primarily on the Scientific Report of the 2025 Dietary Guidelines Advisory Committee (DGAC). This represents a major departure from long-standing evidence review processes that have guided previous editions of the guidelines.

The ASN points out there's a troubling lack of transparency regarding the methods, approaches, and objectives of these newly introduced scientific reviews, as well as the timeframe in which they were completed. This process diverges from gold-standard National Academies of Sciences-recommended steps for building public trust in guidelines.

Why Are Nutrition Scientists Concerned?

The concerns center around several key issues that could impact how Americans view and follow nutrition guidance:

• Transparency Issues: There's insufficient information about how the new scientific reviews were conducted, making it difficult for experts to evaluate the quality of the evidence
• Process Integrity: The departure from established review methods risks undermining confidence in both the recommendations and the science supporting them
• Mixed Messaging: The guidelines contain contradictory advice, such as maintaining the 10% saturated fat limit while encouraging consumption of foods high in saturated fats like butter and beef tallow

The DGAC includes many ASN members and talented nutrition scientists who voluntarily spent considerable time reviewing and analyzing evidence in collaboration with colleagues at the Department of Health and Human Services (HHS) and United States Department of Agriculture (USDA). The new process calls into question both the scientific review process and conclusions in their comprehensive report.

What Does This Mean for Consumers?

The ASN warns that oversimplification of the guidelines in ways that introduce contradictory messaging is likely to further confuse consumers. For example, while the DGAC scientific review found strong evidence that lower saturated fat intake decreases cardiovascular disease risk in adults, the 2025-2030 guidelines maintain the long-standing recommendation to cap saturated fats at 10% of calories while also appearing to encourage greater consumption of certain high-saturated fat foods.

"This mixed messaging may be difficult for consumers to interpret and could inadvertently make it harder for Americans to maintain long-term health," the organization stated in their response to the new guidelines.

Despite these process concerns, the ASN does support the broad eating pattern emphasized in the new guidelines, which focuses on minimally processed, nutrient-dense foods and limits added sugar, sodium, and saturated fat. These dietary approaches have demonstrable health benefits and are linked to improved long-term health outcomes.

The organization remains committed to advocating for transparent, evidence-based scientific processes to develop nutrition guidance that upholds scientific rigor and integrity while maintaining public trust. Both reports highlight the ongoing need for continued investment in nutrition research and increased targeted funding for diet-related chronic disease research at the USDA, Centers for Disease Control and Prevention (CDC), and National Institutes of Health (NIH).