Also https://www.scientificamerican.com/article/why-paleo-diet-ha... I quote: Humans come from a fairly generalized line of higher primates, a lineage able to utilize a wide range of plant and animal foods. There is general agreement that the ancestral line (Hominoidea) giving rise to humans was strongly herbivorous (14, 15). Modern human nutritional requirements (eg, the need for a dietary source of vitamin C), features of the modern human gut (haustrated colon), and the modern human pattern of digestive kinetics (similar to that of great apes) suggest an ancestral past in which tropical plant foods formed the basis of the daily diet, with perhaps some opportunistic intake of animal matter.
Going on: Consumption of animal matter to satisfy requirements for protein and many essential micronutrients would free up space in the gut for carbohydrate-rich plant foods and allow for their use as fuel for the increasingly large human brain (14). Because humans initially evolved in Africa, where wild animals generally lack appreciable fat stores (2), it seems clear that they consumed a mixed diet of animal and plant foods, given the apparent limitations of human digestive physiology to secure adequate daily energy from protein sources alone (4).
Whilst early human were not vegan they were hardly mostly carnivores either. Furthermore as stated in both articles basing the diet of modern humans on the one of our ancestors is a mistake!
P.S. I am far from being vegan! Suturday I ate 600g of a delicious cow.