Background: Food loss and waste over-uses natural resources and is responsible for a considerable share of greenhouse gas (GHG) emissions. Moreover, increasing food prices and growing food insecurity internationally make instances of food wastage appear even more irresponsible and showcase the inefficiencies of the current food system. A new concept in the toolbox for fighting food loss and waste is upcycling – value enhancing use of ingredients otherwise wasted – that leads to upcycled food. However, not all products currently called ‘upcycled food’ live up to the resource-saving and value-adding promise entailed in the idea of ‘upcycling’, and products markedly differ in how ‘radical’ the upcycling is from a consumer perspective. Scope and approach: To shed light on this, we introduce a two-folded definition that hinges on current consumer edibility perception and has a view to changing consumer perception; We show that there are two types of upcycled food which each have a distinct role and contribution to preserving natural resources - one is avoiding resources are wasted that have gone into food production, thus constituting upcycled foods through alternative use, the other is diversifying and broadening the food resource base, thus constituting upcycled foods through novel use. We provide examples of these upcycled food types and highlight potential boundaries from a sustainable development goal perspective. Key findings and conclusions: Mainstreaming the idea of upcycling in food systems has huge potential for improving circularity in the food system. Untapping this potential needs collaboration across the whole value chain and taking a food system perspective, such as when being well-aware of the boundaries arising from the dynamic nature of the topic and the interdependencies.