Alexander, et al (2017), noted that there are losses at every stage in the food system which can otherwise by used to meet nutritional requirements of a growing global population, but that is beyond the scope of this book. However, such waste can be otherwise returned to the farm to enhance productivity. They estimated the magnitude of such waste as to the following extent:
The proportion of global agricultural dry biomass consumed as food is just 6% (9.0% for energy and 7.6% for protein), and 24.8% of harvest biomass (31.9% for energy and 27.8% for protein)
The highest rates of loss are associated with livestock production
Losses of harvested crops at 44.0% of crop dry matter (36.9% of energy and 50.1% of protein) lost prior to human consumption
If human overconsumption, defined as food consumption in excess of nutritional requirements, is included as an additional inefficiency, 48.4% of harvested crops were found to be lost (53.2% of energy and 42.3% of protein).