IAFNS Develops ‘Principles’ to Guide Classifying Foods Based on Processing, Formulation

After careful effort, the Institute for the Advancement of Food & Nutrition Sciences has published a set of governing Principles for how we look at and manage foods that involve processing. The Principles are geared towards guiding researchers and decision-makers who are navigating both controversy and confusion surrounding food processing and formulation.

Processing foods can involve cooling, heating, freezing, mixing, extruding, filtering, cooking, fermenting, drying and forming. These can have positive, negative or neutral impacts on a food’s physical, biological or chemical characteristics. That said, some food classification schemes imply that processing is inherently harmful.

To address such criticisms and identify paths forward, IAFNS formed a Working Group comprised of government, industry and academic scientists. This group in turn charged a separate six-member independent Writing Team composed of public sector researchers to generate a set of principles designed to help researchers and decision-makers navigate this challenging area.

The new Principles advance science by calling attention to the need for classification systems to be: transparent, reproducible, biologically plausible, link to health outcomes (nutrition), distinguish processing from formulation and evolve with advancing science. They call for realism by emphasizing the need for controlled human trials instead of basing decisions on observed correlations between certain foods and health impacts. The authors note that correlation studies alone are limited in their ability to establish causation.

The Principles are also intended to provide a shared foundation and standardized approach to guide researchers in this area without endorsing or advocating for the creation or use of any one particular classification scheme. Some schemes have been criticized due to inconsistencies, ambiguities, limited evidence, misalignment with dietary guidance and potential for overgeneralization. One common critique of the descriptor of so-called ultra-processed foods is that it lacks clarity and is not rigorously defined.

The Principles are also based on IAFNS’ approach to Scientific Integrity which upholds transparency, collaboration, public engagement and public benefit. The 9 Principles were vetted on April 15, 2025, at a cross-sector stakeholder in-person meeting in Washington, DC, funded in part by the Agriculture Department’s National Institute of Food and Agriculture, (AFRI project 1033399). This workshop dialogue included presentations from academia, industry and government.

The Writing Team experts generated a set of 9 aspirational principles that can be used to identify future research priorities and areas for investment while also providing guidance on cautionary action in the absence of complete data.

The nine Principles above are elaborated on in the paper. They are intended to support the development and application of food classification schemes focused on processing and formulation that are transparent, reflect biological plausibility, and are capable of supporting meaningful interpretations and informed actions.

In carrying out their research, the Writing Team concluded that some ways foods are classified are not aligned with other public health nutrition concepts. For example, in some food classification schemes, foods with added fibers fall into the category of the highest level of processing, implying they should be avoided. However, avoiding these foods may be a mistake as fiber intake is one of the largest and most consistent nutrient gaps in the US population.

The Principles are targeted primarily to researchers who are applying classification schemes or interpreting existing science. Other audiences include users of research—such as policy professionals and other decision-makers—and developers of food classification schemes.  

New food classification schemes continue to be proposed. While this work proceeds, foundational concepts remain unresolved, including how these foods are defined and what characteristics are important to health, according to the paper.

In this swirl of science, debate and perspectives, the IAFNS Working Group on Food Classification published the “Guiding Principles for Science-Based Food Classification Systems Focused on Processing and Formulation.” The purpose of the Principles is to foster alignment across stakeholders and support science-based decisions that impact public health.

The nine Principles can be distilled into key themes relevant to food classification schemes, research based on them, and interpretation of such research to inform policy and related decisions. These Principles can serve as a foundation to support impactful research on food classification schemes and, through this, public health policy.

Given the resource-intensive nature of developing, analyzing, or applying food classification schemes, researchers should prioritize efforts with the greatest potential for meaningful impact, the authors found.

In concluding remarks, the authors posit that food classification schemes can be developed and applied for a wide range of use cases, and they may be helpful for those implementing interventions or health policies. In this sense, they offer a framework for assessing whether the research behind such schemes is fit for purpose.

This work is supported by the IAFNS Food Classification Working Group.

The paper is available here.

The Institute for the Advancement of Food and Nutrition Sciences (IAFNS) is committed to leading positive change across the food and beverage ecosystem. This paper was supported by IAFNS Working Group on Science-Based Principles for Food Classification to Support Public Health. IAFNS is a 501(c)(3) science-focused nonprofit uniquely positioned to mobilize government, industry and academia to drive, fund and lead actionable research. iafns.org.