There is a digression early in Knut Hamsun's novel Growth of the Soil, where for a paragraph or two he goes on about how great potatoes are and also mentions the same thing about man needing just potatoes and milk.

It's an incredible novel, and I have read it periodically since I was a teen, with so many great musings on the meaning of life but I always remember the passage on potatoes. Couldn't for the life of me tell you why that's stuck in my head so much.

EDIT

What was that about potatoes? Were they just a thing from foreign parts, like coffee; a luxury, an extra? Oh, the potato is a lordly fruit; drought or downpour, it grows and grows all the same. It laughs at the weather, and will stand anything; only deal kindly with it, and it yields fifteen-fold again. Not the blood of a grape, but the flesh of a chestnut, to be boiled or roasted, used in every way. A man may lack corn to make bread, but give him potatoes and he will not starve. Roast them in the embers, and there is supper; boil them in water, and there's a breakfast ready. As for meat, it's little is needed beside. Potatoes can be served with what you please; a dish of milk, a herring, is enough. The rich eat them with butter; poor folk manage with a tiny pinch of salt. Isak could make a feast of them on Sundays, with a mess of cream from Goldenhorns' milk. Poor despised potato — a blessed thing!

Wonderful

Well I'm for one glad it did. Never heard of this book, but it sounds interesting enough (and not just because of the potato paragraphs) that I just ordered a copy.

Thanks!