Here's a study on historical data, here are some statements:
"Arteriosclerosis and degeneration of the myocardium are quite common conditions among the Greenlander" -- study from 1940
IMO, best evidence ever is on Maasai people, where they find massive amounts of atherosclerosis in the blood vessels of young people and there are multiple cases where young people die of atherosclerosis. Only thing that makes Maasai survive is that they start with this kind of diet at early age, their blood vessels get extra wide and elastic and can withstand the hardening effects of atherosclerosis.
Fiberless diet is a death certificate for the modern western man if one's not on it from birth.
