The Purpose of Food Processing and Ultra-Processed Food: the Potential, Pitfalls and Path Forward for Public Health

The Nova classification considers the purpose and degree of food processing to capture how recent changes in the food system may link with health. Its value for understanding diet-disease relationships is debated. However, reviews typically focus only on its value, or its limitations. Furthermore, by discussing the degree of processing only and not the purpose, or discussing processing in general, reviews of limitations do not address pitfalls of the Nova classification. This conflict and confusion stalls progress to improve public health. Therefore, this review aims to provide a balanced understanding, interpretation and utilisation of the Nova classification and purpose of food processing, with a critical evaluation of its potential value, of pitfalls largely overlooked to date with recommendations to avoid unintended consequences, and constructive reflections on a path forward.

The Nova classification offers a framework linking upstream socioeconomic factors with downstream properties of available food, complementing existing food-based dietary guidance to improve access to healthy diets through food systems transformations. However, its practical application, narrative of intrinsic harm of ultra-processing, usage to guide diets in isolation, and overemphasis on mechanisms with weaker evidence are pitfalls that, whilst avoidable, can have unintended consequences. There is agreement on the need for food systems transformation to ensure access and affordability to healthy diets for all. For public health, the purpose behind food processing provides an understanding of systems drivers of food production and accessibility. This consideration can be reflected in policy to improve access to healthy diets, without necessarily explicit use of the Nova classification.