> So what did paleo Scots eat? I still eat oats once in a while,
> especially in winter, or in cookies.

I have Scottish ancestors as well but they went over the other pond in 1604
and disembarked  in Gothemburg .

I guess that Britain was a bit earlier in changing their crops compared to
Sweden but this is a bit of the cereal history of Sweden. Barley has been
cultivated here for a few thousand years, rye for about 1000 years and at
the beginning of 1800 barley and rye dominated. At that time we and the rest
of Europe started using horses to work the lands and horses worked well on
oats so then we started growing and exporting it, especially to Britain. It
was not for people to eat at that time. Guess what? Comes 1900 and tractors.
Tractors don't go well on oats. Let's market it as food for people! That
marketing campain was a success in Sweden. Eating oat meal porridge was
considered a morally outstanding activity almost garanteeing its consumer a
place in heaven.

Now about 10% of  the barley we cultivate is sent to Scotland to become
whisky.
Cheers
Eva