[LarryLied]

the diet of pre-agricultural humans was derived primarily from animal based foods.

So why do we have teeth designed for a mixed diet, one which is not primarily meat? Our intestines would be shorter too if meat was our predominate food.

[Pharmboy]

Predominate is the key word here--between about 50 and 60% of total calories. Our small intestines are in between the lengths of the pure carnivores and the herbivores. We are obligate omnivores.