Revisiting the Ultra-Processed Food Concept: A Critical Review of Its Scientific Basis and Implications for Food Classification

The NOVA classification groups foods according to the extent and purpose of industrial processing, and observational studies have associated high consumption of ultra-processed foods (UPFs) with adverse health outcomes. Whether the degree of processing alone is a sufficient criterion for assessing food quality, however, remains under debate, since observational associations do not by themselves identify processing as the causal factor. This review critically examines the conceptual basis of the UPF category and the relationships among food processing, formulation, nutritional quality, and health. Processing can have beneficial or detrimental effects depending on the technology, formulation, and food matrix involved: it may improve safety, shelf life, digestibility, bioavailability, and sustainability, but may also reduce the content or functionality of sensitive nutrients and bioactive compounds. Examples from reformulation, functional foods, clean-label development, sugar replacement, and innovative technologies illustrate these interactions. Nutrient Profiling Models, the Nutrient-Rich Food Index, the Food Naturalness Index, and dietary inflammatory indices are discussed as complementary approaches with their own limitations. We conclude that food quality is unlikely to be captured by the degree of processing alone and that future classification systems should integrate nutritional quality, food matrix, formulation, processing, health outcomes, and sustainability.