Research has discovered that ingesting raw nuts and seeds with the enzyme inhibitors intact can actually be harmful, resulting in gastrointestinal problems, an enlarged pancreas and a condition that leads to the excretion, and therefore loss, of valuable enzymes. Therefore, it is safer and healthier to eat un-sprouted nuts and seeds in a cooked rather than a raw state.
In nature, nuts are encased in a shell that makes eating them slow and difficult. Early humans with other food options would probably not have eaten many raw nuts. It can be assumed from this and from what we know about how difficult they are to digest that we are not designed to subsist on large quantities of raw nuts seeds.