What and how we eat have important environmental impacts, with 26% of anthropogenic greenhouse gas emissions globally attributed to the total food supply chain. 1 As a response to the urgent need to address the climate emergency, research assessing the environmental impacts of dietary intake have increased, informing recom mendations on sustainable diets. 1, 2 However, the majority of this work does not adequately address the role of food processing on the environment. We argue that food processing, and ultra processing in particular, should be an integral part of the way we think about food sustainability.

Ultra-processed foods (UPFs), as defined by the NOV A classification, are industrial food and drink formulations made of food-derived substances and additives, often containing little or no whole foods. Typical examples of UPFs are biscuits and confectionery, chicken nuggets, sugar-sweetened beverages, margarine, and many readymade meals. The purpose of ultra processing is “to create branded, convenient (durable, ready-to-consume), attractive (hyper-palatable) and highly profitable (lowcost ingredients) food products often designed to displace all other food groups”. 3 The rapid global growth in UPF consumption means that there is an urgent need to scrutinise the health and environmental impacts of UPFs. Although evidence that UPFs are harmful to health is accumulating, 4, 5 we know little about the environmental impacts of UPFs and what, if any, role they should play in the transition to sustainable diets. We identify several ways that ultra processing should be considered when estimating environmental and health impacts of diets. Many UPFs contain palm and soy oils, which have substantial negative health and environmental effects. However, the environmental impacts of UPFs go beyond the immediate resources used in the production of their ingredients. In previous work, such as the EAT-Lancet Commission on healthy diets from sustainable food systems, 2 the environmental impacts of diets are based on the effect of the production and demand of agricultural commodities. Environmental impacts of processed foods are poorly quantified, considering only the effects of the primary commodities used for their production