So for the zillionth time the most comprehensive data we have on this is the "Ethnographic Atlas" by Dr. George P. Murdock. Its the basis of Cordains analysis and for many published studies regarding nutrition and health of various societies.
When analyzing the data we find that out of 229 hunter gatherer groups 46 get MORE than 85% of their calories from hunted food. Oh, before we get too far please note that Murdock indicated that gathering activities could also include the collection of small land fauna (insects, invertebrates, small mammals, amphibians, and reptiles); therefore, the compiled data may overestimate the relative contribution of gathered plant foods in the average hunter-gatherer die. So we already have over 20% of the studied peoples eating what is for all intensive purposes a VLC diet.
So 20% of the 229 eat VLC.... I could rest my case here because this alone is enough to prove that the human organism can and will acclimate to a low carb lifestyle without breaking down into disease or ill health, but take a look at the whole of these examined. As a whole they average 70% of their calories from hunted food and 30% from gathered..... that would be a MAXIMUM of 30% carbohydrate load and quite likely to be substantially less due to the inclusion or small animals, insects...ect in the gathered group.
I didn't feel I had to spell this out for you yet again, but there you go. All specific and even referenced for ya.
If you want to delve into history further than what that knowledge shows then you ARE guessing! They may be educated guesses, but none the less are quite debatable. Humans surviving the ice age, following river and costal lines out of Africa....ect. All quite interesting, but I wouldn't put all my eggs in any of those baskets. I look to "wild" humans we know rather than guessing at times past.