The NOVA system can be used to address harmful foods and harmful food systems

Food systems include all of the interconnecting processes involved in producing, distributing, and retailing food.Food systems currently contribute around one-third of global greenhouse gas emissions [1], and the unhealthy food and diets they deliver account for around 15% of deaths globally [2].Both the human and planetary harms of food systems are unequally distributed with less affluent individuals, communities, and countries enduring the greatest impacts [3].Addressing these problems of harmful foods delivered by harmful food systems requires interdisciplinary research and cross-sectoral policy action.Researchers must focus on both identifying the foods causing most harm to human and planetary health, as well as the aspects of food systems that mean those foods continue to be produced.This demands attention from both life and social scientists.The NOVA system offers a new way to approach the simultaneous problems of harmful foods and harmful food systems.NOVA categorises foods into 4 groups based on "the extentAU : Please and purpose of the industrial processing they undergo" [4] (emphasis added; Table 1).The ultraprocessed foods (UPF) that NOVA identifies are often very convenient and palatable and are branded to create social value that extends beyond their nutritional content and taste.For example, many brands aim to associate themselves with aspirational lifestyles.UPF have become common concepts in both the life and social sciences.Life scientists have documented associations between consumption of UPF and morbidity and mortality from numerous causes and have explored biological mechanisms explaining these associations.Social scientists have documented the tactics used by the small number of transnational companies that dominate the global UPF supply to drive demand and minimise attempts at regulation such as front-of-pack labelling and restrictions on advertising.By including both "extent" and "purpose" in its definition, the NOVA system inherently incorporates this duality of life and social science paradigms.By providing a unifying concept around which we can address the key questions of both which foods, and which aspects of food systems, cause the most harm, this duality is perhaps the key added value that the NOVA system has to offer.Unfortunately, this may also lead to a paradigm clash between life science and social science uses of the concept, focused on the "extent" of industrial processing and the "purpose" of industrial processing, respectively.This potential for paradigm clash may prevent the real value of the NOVA system from being achieved.Much of the current academic, policy, and media attention on UPF focuses on the extensive epidemiological literature reporting links between the extent of UPF consumption and health harms.There are primary studies, systematic reviews, and umbrella reviews reporting these harms [5].In the substantial commentary that accompanies these studies, there is debate about the specificity and reliability of the categorisations made using the NOVA system, whether we can interpret evidence from prospective cohort studies as causal, the limitations of the one