Human food vs. animal feed debate. A thorough analysis of environmental footprints

Currently, a large portion of grain production is funneled into animal feed despite widespread hunger and undernutrition. In the present work we: (i) estimated the area, water and carbon footprints of animal-source proteins (AP) obtained from intensive farming systems and compared them with those from producing an equivalent amount of plant-source proteins (PP); (ii) postulated a set of straightforward hypotheses to recover environmental resources by cutting down a surplus in the per capita protein intake from three representative regions where intensive animal farming systems account for a great share of animal food production. Our major findings revealed that AP from intensive farming were approximately 2.4 to 33 more expensive in terms of area and water demand and 2.4 to 240 more pollutant in terms of greenhouse gas emissions when compared with PP. Environmental recoveries varied widely according to the hypothesized scenarios, but even the lowest estimates suggested remarkable results. Whether additional proteins supply would be required, crops with large protein content as peas, chickpeas, soybeans, and lupins could help to meet food security, while better compromise between dietary habits and environmental protection could be reached in rich countries by a moderate consumption of meat produced with non-feed grain systems.