I'm about to toss all my eggs into the low-protein basket as I have yet to see anything convincing me that any protein in excess of nitrogen balance is a good thing and nitrogen balance can be achieved in remarkably low amounts (30-50g/day).
I've been thinking about mentioning that in re: eggs, how easily that can alter protein intake even with little muscle meat. I remember when you commented in my journal about how even though my percentage 18:04:78 p:c:f, was quite low that my level in grams was high at 129 g protein, 33 g carbs and 268 g fat due mostly to eggs. I havn't calculated recently, but I'm sure its much lower protein now.
If you look into Nora Gedgaudas work (which I'm sure you have) she suggests a similar logic, but basically when one does the math, its unlikely to have such a low protein (in grams) without having a very low intake in total calories. The only way in doing so, of course is eating vast amounts of ruminant fat ( or dairy fat, or fruit and plant fats and oils I suppose) which would mean in nature either scavenged, or discarding a large portion of the kill based on its high protein.
It could be suggested that this issue was indeed a factor in Inuit health
or validates some of the more 'superficial' findings about cave peoples in terms of life span etc...but in a way going with the low-protein, it would make me more convinced that the ratio of carbs was probably much higher, or that its requirements higher for carbs and were unmet during worldwide disapora.
I tend to believe it might be somewhere in the middle, with protein being at a similar level in terms of a percentage (perhaps slightly higher than 10%), but probably a much higher level in amount (grams) with total energy expenditure with primitive hunters being far increased.
At the very least, eating a moderately low protein intake with a large percentage of raw animal fat, must have benefits in itself compared to high protein diets or even SWD, even if it is not in absolute low levels of protein, and given for fat-burners that protein doesn't create abnormal amounts of glucose.
anecdotaly, I've tried eating protein intermittently with fat only meals, its pretty challenging. Eating say a few .25 lb muscle meat/fat meals, with a few eggs at other times of the day seems pretty reasonable to me right now, but I'm considering other experiments myself.