No abstract

There is currently little agreement on the optimal ratio of animal-sourced (ASP) versus plant-sourced proteins (PSP) in sustainable human diets. We deployed a biophysical optimization model to find the optimal ASP:PSP ratio at current and recommended protein intake levels for the EU28 countries. Results show that the lowest environmental impact for both land use and greenhouse gas emissions is achieved at a recommended protein intake of 46 g protein/cap/day with an ASP:PSP ratio of 40:60 (18 g ASP/cap/day). At current protein intake (82 g protein/cap/day), the optimal ASP:PSP ratio for land use ranges evenly between 22:78 and 60:40 (18 and 49 g ASP/cap/day) while for greenhouse gas emissions the optimal ASP:PSP ratio is at 40:60 (18 g ASP/cap/day). Diets containing less than 18 g ASP/cap/day show micronutrient inadequacies, leading to increases in both land use and greenhouse gas emissions.

The global food system is facing the challenge of producing sufficient nutrients to accommodate future demands within planetary boundaries, while reducing malnutrition. Although nutrient-rich seafood can play a prominent role in resolving this challenge, seafood from capture fisheries is currently partly wasted. The aim of this study was to quantify the nutrient contribution from capture fisheries under the assumption that all captured seafood and byproducts from seafood processing would be used for human consumption. Our results show that available seafood per capita can be doubled without increasing harvest when all reported, illegal, and discarded capture as food, complemented with processing byproducts are used. Moreover, seafood contributes significantly to daily nutrient requirements – e.g., omega-3 can be fully met. These results indicate that putting the whole fish on the table can increase nutrient availability from capture fisheries substantially and sustainably.