A friend casually mentioned to me the other day that on the Lewis & Clark expedition, the first expedition to really explore the US territories outside the Eastern settled territory, the members of the party consumed up to nine pounds
of meat per day but still had trouble maintaining weight since the greatest difficulty they had was finding carbs in the quantity needed for the party. Curious about this, I decided to check it out and sure enough, found that there is documentation of this meat consumption. For an interesting read on this check out http://lewisandclarktrail.com/hunting.htm
Of course, the chief reason for the difficulty in maintaining weight was the prodigious amount of work they were doing during a routine day plus the fact that on many occasions they simply could not kill sufficient game for the party. Apparently they must've nearly starved to death on occasion.