I believe you misunderstood Mars' post. I believe her use of the word "concocted" was intended to indicate that the folks who came up with that had their hearts in the right place, but came up with poor one-size-fits-all advice on the basis of insufficient evidence (Mars, correct me if I'm wrong!).
Regarding how many links people post, if people are just sharing their experience, there's no need for them to post a link.
Early humans did need to dramatically increase their calorie intake (over the amount required by proto-humans) to develop and fuel their large energy-intensive brains. More humans began hunting and some sub-populations ate high amounts of animal products but but others ate high carb (e.g. wild yams and other tubers) and some switched depending upon availability. The amount of animal-derived calories that was fat vs protein also probably varied (those eating more snail and mussels as their animal sources not getting much fat from them). In addition to adding more animal products to their diets (relative to pre-human predecessors), some ancient humans also employed cooking and pre-agricultural plant management to increase available calories.
Here's a stat regarding modern hunter-gatherers, which people used as a proxy for ancient diets:
"According to recent analyses by Loren Cordain of Colorado State University, contemporary hunter-gatherers derive, on average, 40 to 60 percent of their dietary energy from animal foods (meat, milk and other products)." (from: http://docencia.med.uchile.cl/evoluc...sciamdieta.pdf
40 -60% is an average, and includes both fat and protein. I'm sure that even today there are hunter-gatherer cultures that fall far outside that range, particularly for periods of time. There would also be some additional fat in the non-animal sources, but I see no reason to think that all early humans ate a high fat diet.
Here's a quote about what was known about Middle Eastern diet just before the advent of the agricultural revolution:
"Foods known to be gathered during the Mesolithic period in the Middle East were root vegetables, wild pulses (peas, beans, etc.), nuts such as almonds, pistachios, and hazelnuts, as well as fruits such as apples. Seafoods such as fish, crabs, molluscs, and snails also became common during this time."
, this isn't a research paper, but at least it provides a source reference.)