>So maybe  100,000 years ago some grain may have been eaten
>for several months of the year when the persons were
>desperate;

The very important difference between wild and "tame" grains
is that the wild seeds fall off as soon as they ripe. The
early farmers took advantage of a (rather usual) mutation
that makes them stay on the stalks. Grains with that kind of
mutation need human help to get any offspring.

Agriculture started on mountain slopes where newly ripe
grains could be found for a longer time as they ripe later
the further uphill they grew. This goes for all three places
where agriculture started independently, Middle East, China
and America.

And I think a lot of vegetables that can only be had in small
quantities have been eaten in all our history. Maybe also in
large amounts, to result in bigger population, but worse
health. There is nothing in the evolutionary mechanism that
says that it results in completely healthy individuals.

- Hans