Abstract
Background/Objectives: The nutritional importance of grain-based foods (GBFs) and whole grains (WGs) is underscored by their central position in dietary guidance worldwide. Many jurisdictions recommend consumers increase WG intake because they are associated with multiple health benefits, with evidence quality rated as moderate to high. High intakes of ultra-processed foods (UPFs), as defined by NOVA that classifies food by level of processing, are associated with numerous negative health outcomes, with evidence less convincing than for WGs. Yet, some dietary guidance recommends consumers to avoid UPFs. This creates two divergent guidelines since NOVA designates most commonly eaten grain-based foods (GBFs) as UPFs. These contradictory guidelines fail to comply with recommended principles of dietary guidance and generate questions about underlying assumptions and definitions that classify WG staples and colas together. Methods: Definitions and assumptions for systems ostensibly categorizing foods by level of processing were evaluated for validity by various methods. Special attention was paid to the ability of different classifications to differentiate between WGs, RGs staples, and indulgent GBFs. Findings from meta-analyses associating high intakes of WGs with numerous health benefits were compared with those associating high intakes of UPFs. Menus and modeling studies were assessed for ability to meet recommendations for WGs and the grain food group with customary GBFs while avoiding UPFs. Advice to "avoid UPFs" was tested against principles for effective dietary guidance. Results: Definitions and categorizations of foods by levels of processing vary markedly. Assumptions for NOVA and other systems are questionable. While meta-analyses consistently show high intakes of UPFs are associated with adverse health outcomes, high intake of WG foods, nearly all designated as UPFs, are associated with better health outcomes, although evidence quality for the latter is rated stronger. These findings add to the body of evidence suggesting flawed assumptions behind categorizing WG staples in terms of level of processing. Conclusions: NOVA deems 90% of WGs as UPFs. Adding statements to dietary guidance to "Avoid UPFs", while asking consumers to increase WG intakes, confuses. Further, it jeopardizes efforts to increase intake of fiber and WG foods because it excludes top sources of fiber and WG-based breads, rolls, tortillas, or cold cereals in Western diets. NOVA advice to avoid UPFs challenges principles for usable dietary guidance and the construction of culturally appropriate, healthy dietary patterns containing WG staples from all levels of processing.