The role of dietary protein in a healthy sustainable diet.

There are many scientific publications with several hypotheses that can assure a sustainable diet for the growing population. To reduce the environmental impact of food systems, one of the main suggestions provided in these scientific publications is to reduce or remove the animal source foods (ASF) from diets, especially in the diet high income countries. These studies, however, do not satisfactorily consider nutritional differences in the food products from different sources such as ASF and plant source foods (PSF). While considering environmental impact, influence of diet on the health of individuals should not be overlooked. The major concern of the food production systems is to assure healthy, sustainably produced food products for the growing population globally. Food production systems have major environmental impact which results in climate change including the uses and availability of natural resources. For instance, food systems alone contribute up to 30% of global greenhouse gas emission. More than half of which comes from animal production systems alone. One of the promising ways to sustainable food production is circular food production system, which assures uses of both plant and animal systems to support each other. The circular food system, in addition to sustainably produced PSF, can provide highly nutritious ASF in a sustainable manner as well. For example, animal based protein sources can supply approximately 1/3 of the total protein supply with the lowest environmental footprint. The adequacy of quality proteins in a diet, defined in terms of indispensable amino acids, play a major role in healthy functioning of the body. To achieve a healthy sustainable food production system, it is important to assure both the quality of the diet as well as minimum impact on the environment. Therefore, the objective of this study is to understand the role of protein quality of individual food-ingredients, food-products, meals and diets in shaping a healthy and sustainable diet. To achieve the aim of the study, a bio-physical model called CiFoS will be used. This model facilitates choices of combinations of crop rotations and farm animals that minimizes agricultural land use and greenhouse gas emissions, while meeting the daily-recommended macro- and micro-nutrient requirements. Adaptation in the model will be made in terms of protein quality at different level of food consumption and daily requirements. This study aims to highlight the importance of protein quality in defining a healthy sustainable diet.