Sustainability in relation to the human food chain is defined as the global balance/equilibrium between efficient use of limited natural resources (such as arable land, water, fuel, etc.), emissions (e.g., carbon dioxide, methane, nitrous oxide (laughing gas), etc.), and socio-economic and ethical aspects as a basis for the existence of future generations. Sustainability in the production of food of animal origin or edible protein necessitates efficient production. Efficiency calculations should not be limited to only the food chain links ‘feed—animal—food of animal origin’, but should include the entire food chain. A system has the highest efficiency or the greatest sustainability if it is impossible to improve one parameter without deterioration of one or more of the other parameters. The present review is divided into two parts. In the first, the authors define the term sustainability and the objective of the paper. Protein of animal origin is the main topic and is the focus of the chapters regarding resource inputs in the form of arable land, water, fuel, etc., and outputs in form of animal yields and emissions such as carbon dioxide, methane and laughing gas. Carbon Footprints (CF) as an ‘overall measure of emissions’ are defined.