Are all ultra-processed foods bad? A critical review of the NOVA classification system
Jimmy Chun Yu Louie
Abstract
The NOVA food classification system and its categorisation of ultra-processed foods (UPFs) have significantly influenced dietary guidelines worldwide, yet the assumption that all UPFs are uniformly harmful warrants critical examination. Here, a review of evidence revealed substantial heterogeneity in health outcomes across UPF subtypes, with products like sugar-sweetened beverages consistently associated with adverse outcomes while fortified cereals and certain dairy products demonstrate neutral or protective effects. The binary nature of NOVA's classification fails to account for nutritional composition, fortification benefits, and cultural food traditions, creating inconsistencies in categorisation across different contexts. Methodological limitations in UPF research include inadequate dietary assessment tools, selective reporting of negative findings, and experimental design flaws that conflate processing with other dietary factors. Implementation challenges extend to socioeconomic accessibility, as UPFs often provide cost-effective nutrients for disadvantaged populations and environmental sustainability, where wholesale reduction could increase resource demands. Future directions should develop more nuanced classification systems that integrate processing methods with nutritional quality to better inform public health strategies rather than categorically rejecting all UPFs.