New scientific principles address “highly-processed” gap in US dietary guidelines

The Institute for the Advancement of Food and Nutrition Sciences (IAFNS) has published nine guiding principles for classifying foods based on processing and formulation, as the US food industry grapples with new national dietary guidelines that call on Americans to avoid “highly processed” foods, but without providing an operational definition. 

The principles, developed by an independent team of public sector scientists, aim to establish scientific standards that address recurring criticisms of existing classification systems — including the widely used Nova framework — while US and international regulators work separately to define “ultra-processed” foods (UPFs) for the first time. 

The 2025–2030 Dietary Guidelines for Americans, released earlier this month by the US Department of Health and Human Services, is the first federal nutrition guidance to explicitly tell consumers to “avoid highly-processed, packaged, prepared, ready-to-eat, or other foods that are salty or sweet.” 

But the guidelines use the term “highly-processed” rather than “ultra-processed,” and the 20-member Dietary Guidelines Advisory Committee stopped short of making specific UPF recommendations after grading the evidence linking UPF consumption to obesity as “limited.”

The Institute of Food Technologists (IFT) quickly called for clarification, warning that additional detail and clarification will be important to ensure consistent interpretation and effective implementation across federal and state nutrition programs. The organization has long argued that existing classification systems broadly categorize foods by processing intensity without considering nutritional composition, leading to misclassification of nutrient-dense foods such as whole-grain bread and yogurt.

Principles target recurring criticisms

The IAFNS principles directly address these concerns. Chief among them: classification schemes should be reproducible and transparent, properties used to differentiate foods must have demonstrated biological links to health outcomes, and — critically — processing and formulation should be evaluated as distinct concepts rather than conflated.

“Food classification systems must be underpinned by rigorous and transparent documentation to enable consistent and appropriate applications,” the paper states. Processing refers to methods that transform agricultural products into food, while formulation describes the selection and proportioning of ingredients — a distinction the authors argue has been lost in systems like Nova.

Defining “highly-processed” foods and their health outcomes is an ongoing process.The principles also emphasize that “associations without robust causal evidence should be considered preliminary.” This challenges existing systems that critics say rely more on associative logic than validated health outcomes. 

A modeling study cited in the paper found that a diet primarily composed of Nova-classified UPFs can be designed to meet most nutrient requirements and achieve a high diet quality score — highlighting what the authors describe as misalignment between some classification systems and prevailing dietary guidance.

The IAFNS Working Group includes committee members from major food companies, such as ADM, Cargill, Coca-Cola, General Mills, and Kraft Heinz, alongside academic advisors from institutions such as Wageningen University and Penn State. The independent Writing Team that drafted the principles was composed solely of public sector scientists, and the work is supported by both IAFNS and a USDA National Institute of Food and Agriculture grant.

Soy sector flags nutrient content over processing

The soy industry has struck a cautious note on processed food messaging in the new guidelines. The United Soybean Board welcomed the guidelines’ continued recognition of soy foods — including tofu, tempeh, and fermented products like miso — but flagged concerns about how processing-based frameworks assess healthfulness.

“While limiting processed foods is included in the guidelines, it’s important to keep in mind that a food’s healthfulness is best measured by its nutrient content and how it affects health — not merely its processing level,” the organization states. “In the case of soy foods, methods such as fermentation and fortification support nutrition, food safety, and accessibility.”

This stance aligns with the IAFNS principles’ emphasis on biological evidence. Julie Ohmen, CEO of the Soy Nutrition Institute Global, points to existing regulatory recognition: “Concentrated sources of soy protein lower blood cholesterol levels, which is why the US FDA’s health claim is used for foods containing sufficient amounts of soy protein per serving.”

Regulatory landscape in flux

The lack of an operational definition for UPFs remains a central challenge. The FDA and USDA issued a Request for Information last year seeking data to develop a uniform federal definition — the first concrete step toward grounding the discussion in evidence. The International Dairy Foods Association has cautioned that undefined terminology risks “discouraging consumption of nutrient-rich foods that are vital to public health.”

Beyond the US, the World Health Organization (WHO) announced in May 2025 that it is developing global guidance on UPF consumption. A guideline development group has now been formed following an open call for experts, with the WHO stating the guidance is “much needed” and will complement existing recommendations on macronutrient intake. The process has drawn scrutiny from some food scientists who argue the expert panel lacks diverse perspectives on the UPF debate.

Innova Market Insights data shows one in four consumers globally say they are eliminating processed foods from their diets, while nearly half report purchasing more fresh, unprocessed foods over the past year. Yet consumer confusion persists — research from EIT Food Consumer Observatory indicates many underestimate how much UPF they actually consume, likely due to difficulty identifying these foods.

Whether the IAFNS principles will influence how regulators ultimately define UPFs remains to be seen.