The participants in this debate agree that food processing vitally affects human health, and that the extent of food processing significantly affects diet quality and health outcomes. They disagree on the significance of ultra-processing, as defined within the Nova food classification system. The YES position holds that the concept is well-founded, clear, and supported by a wealth of investigations, as demonstrated by systematic association between ultra-processed food (UPF) intake and various diseases and disorders, and the persistence of these associations with control for critical nutrients. The NO position argues that the concept of UPF is poorly defined; gives rise to misclassification of foods; is without clear mechanisms of action; and that the observed associations with obesity are likely confounded. The YES position argues that the Nova system is therefore crucial to inform dietary guidelines and also public policies designed to reduce production and consumption of UPFs, whereas the NO position argues that the system adds no value to conventional nutrient metrics and existing nutrient profiling systems, pointing instead to the need to develop an evidence-based system to characterize obesogenic foods.