Just How Inefficient is Our Food System?

According to this post over at TreeHugger, it's pretty bad. To wit:
America, a new study suggests, wastes 40% of its food supply annually. Published in the Public Library of Science, the research indicates a dramatic increase over the last decades, up from 28% in 1974.
The full post outlines some of the nuance behind those figures, but the final number is no less shocking.