It is hard to open a newspaper or lifestyle magazine now without finding the concept of ‘ultra-processed food’ somewhere mentioned. Based on the idea that not only a product’s content but the processes involved in its manufacture determine its health value, UPF has captured public attention. How useful is the classification, and what can its use achieve? In this TABLE Letterbox Exchange, Rob Percival, Anthony Warner and Mike Rayner were asked to consider in their debate i) the multiple understandings of the UPF concept, ii) the context and conditions of its successful or unsuccessful use, and iii) the relative goals and outcomes of i) and ii). The Letterbox will feature a total of nine letters. Read more about the origins and terms of the concept in TABLE’s UPF Explainer. 

In the quest for sustainable healthy diets, it is common to hear recommendations to reduce the amount of animal-sourced foods consumed in high-income countries. But what level of reduction is optimal for human health? For the best nutritional and health outcomes, should we be eating low-meat “flexitarian” diets, or entirely plant-based diets? In this Letterbox exchange, nutrition researcher Flaminia Ortenzi and physician Dr Tushar Mehta share their perspectives on the relative health and nutritional impacts of purely vegan diets compared to those that contain low levels of animal-sourced foods. Flaminia focuses on the nutrient density of different foods, while Tushar discusses data on the health outcomes of different diets.  

Rewilding, with its promise to bring back some wildness to landscapes, is attracting both excitement and controversy in the UK. But could rewilding in the UK simply cause more damage to biodiversity elsewhere?  

The future roles of livestock and alternative proteins are heavily contested. The IPES-Food report The Politics of Protein: Examining claims about livestock, fish, ‘alternative proteins’ and sustainability aimed to overcome polarisation by critically assessing the stories commonly told about different proteins and their environmental, nutritional, and social impacts. Did the report achieve its goal? In this TABLE Letterbox exchange, Garrett Broad and Phil Howard discuss whether the report instead reinforced existing media narratives about alternative proteins, and debate the extent to which plant-based and cell-cultured foods can help to resolve the challenges facing the global food system.

In this Letterbox series, Hiwote Bekele and Tesfaye Shiferaw Sida (PhD) debate the Ethiopian government's approach to regulating the cultivation of genetically modified organisms. Hiwote and Tesfaye will be exchanging further letters on this topic: leave your comments at the bottom of the page to help steer the discussion.