The Eades point out that Egyptian mummies, probably the best source of ancient pathological data, exhibit exactly the same proportion of the four major metabolic disorders as contemporary people. And their diet was very close to that recommended by the AHA, mostly whole grains supplemented by lesser amounts of lean poultry and fish.

Perhaps a good example to look at for how long it takes to adapt to a radically different diet is the panda, which is essentially a bamboo-eating bear. How long did it take for the panda forebears to emerge as herbivores?