Then I'm the poster boy - 1/2 Kraut & 1/2 Limey. Speaking of which (limes), let me assure you, our N. Europe ancestors well knew the necessity of preserving fruits/veggies from the summer/fall harvests. Scurvy can occur from lack of Vit C within a month or so.
For some reason, we think of historical times as lacking in communication, yet a key part of most local economies was trade. Food stuffs were constantly coming in to supplement local diets in exchange for the meats (salt preserved), furs, etc found in the northern latitudes.
You're right about potatoes/corn being fairly recent (500 yrs ie Columbus), but many point to the explosion in European populations as a result of these new imports. I've heard that Ireland's population is still less than it was in 1847 before the famine - that's how dependent people became on these essential foods.
Not to wax too estatic about potatoes, but I happen to metabolize them extremely well. Because they are also chock full of vitamins (C, etc), you could really almost live on the them to the exclusion of anything else in a pinch.
However, I am a carnivore, and like nothing better than to stuff myself silly at least once a week from some poor animal's carcass. Speaking of which, is it the weekend yet?