going paleo... the sapiens way

fruits, vegetables, oily seeds and meat. no grains and no diary. this is what is usually called a paleo diet. maybe it's not as popular as some years ago, but there are still many people around that decide to go paleo and to eat like our ancestors.
but are we sure that our species in the paleolithic era used to eat this way? surely there were some humans that used to eat lots of bushmeat, but their surname was neanderthal, they went extinct without leaving any significant bond of direct descent with the later species of hominids. our most direct ancestor from the paleolithic age was the homo ergaster, that many anthropologists consider as a subspecies of homo erectus. the ergaster was a kind of superhuman: the average height was 180 centimeters for the males and 167 centimeters for the females, so way more than today. the average size of brain was bigger too (1500 milliliters compared to today's 1240). the average weight was 66 kilograms (the 180cm-66kg ratio should make us reflect on how a human body is supposed to be in a natural state). still, the most interesting data is about longevity: mortality rate during early childhood was quite high but individuals who managed to survive the first 2-3 years of their life had a life expectancy between 74 and 80 years, quite similar to the most optimistic values of today. to grasp the actual meaning of these statistics, let's imagine a standard of living without any kind of medication, where even the smallest and most trivial wound can lead to infection and become a real risk and where any adverse weather event can be deadly dangerous. so a life expectancy between 74 and 80 years means that our ancestors were extremely robust and in perfect health.
the lifestyle of our ancestors during this stage of our evolution was extremely active: they moved all day looking for food, and every new ground they explored represented new challenges to face both physically and intellectually. they fed on all the vegetables they could find, be it fruits and leaves but also seeds, roots and legumes. those were the conditions that influenced permanently our evolution.
so... no meat? until some decades ago it was common belief that eating meat played a crucial role in our evolution and that hunting was the first trait to set us apart from other apes. actually that was a big misunderstanding about the role of meat consumption during the paleolithic era. luckily, since the 80s many anthropologists shed some light on this subject. our ancestors ergaster used to hunt big game, but only on rare occasions and it wasn't considered a source of food. big game hunting was a way to create social cohesion within a group and to establish a hierarchy among the males by showing force, bravery and endurance. the few times that the hunt actually finished with the killing of an animal, our ancestors just couldn't eat their prey, except for small portions. there are many evidences backing up this theory: anatomically, the ergaster wasn't able to throw something against a prey with enough precision to actually hit and kill it. from a nutritional point of view, bushmeat is very low in fat and very rich in protein: our body assimilates and turns into energy just little portions of protein (that's what causes the temporary weight loss occurring with the low-carb hi-protein diets) causing the creation of lots of waste products. so eating bushmeat would translate into a calorie intake so low that it couldn't compensate the energy used during the hunt, and a quantity of protein so high that it could actually be considered toxic for our body. even the simple act of chewing raw bushmeat is nutritionally uneconomical: a human being would burn more energy chewing it than he would gain digesting it. plus, in climatic conditions like those of the savannah, meat would remain edible just for a short timeframe, probably not even the time required to chop up a prey and chew the pieces.
so the homo ergaster actually ate some animal protein but, much like other apes, in an extremely low quantity and incidentally, usually in form of bugs and small animals that were swallowed with vegetables, and obviously such a small intake of animal protein had no relevance in the physical evolution of our species.
so if we want to go paleo and eat like our ancestors, we should feed ourselves just on fruits, raw vegetables, roots and oily seeds, and this is actually the way of eating of our cousins gorillas that have a digestive system extremely similar to ours. introducing meat in our diet would mean going neanderthal and not paleo.
why should we imitate the habits of someone who lost his battle for evolution ages ago and went extinct?