You know, I read that back in college, was properly outraged, resolved to eat all the food I served myself for every meal and never serve myself more than I would eat from then on, have done so ever since, and then proceeded to forget my original reason for doing so? That figure had passed out of my mind until you brought it up just now.

That said, the efficiency gap, while large, is still considerably less than that between raising meat and produce, so a person would actually be wasting fewer resources if they were eating only produce and served themselves a 40% excess beyond what they could eat and then threw it way than if they were eating a meal where meat constituted a significant proportion of the serving, and took only as much as they could finish.