Population protein intakes and food sustainability indices: The metrics matter

Abstract It is common practice in food sustainability studies to calculate population-based average protein intakes and express environmental footprints on a gross protein basis. Such analyses, however, assume that the requirement for protein is also expressed as gross protein which is not the case. This ignores the critical role of dietary protein as a supply of dietary indispensable amino acids, and does not account for differences in the protein quality of foods. Previously published datasets are re-analysed here to express population protein intakes and environmental footprint data on an available protein basis, accounting for both amino acid digestibility and utilization. When protein quality is taken into account, for many countries of the world protein is found to be deficient for the average adult, and different rankings are found for various environmental footprints.