OK first of all, now I'm not sure what it was that Bourdain was served that was called "mountain potato". It was probably Nagaimo, but maybe in a special kind of preparation. In any case, I dug up this quote about natto and nagaimo:
I thought I would die. Nothing, not bugs, not iguana, not live reptile parts, not tree grubs, nothing I'd ever eaten would approach the horror of these few not unusual breakfast items. I'm not sneering. I'm sure that natto AND mountain potato are, as they say, 'Acquired tastes.' And I'm sure that over time I could learn to appreciate them. If I were incarcerated and natto was the only food available. But for right now? Given a choice between eating natto and digging up my old dog Pucci (dead thirty-five years) and making rillets out of him? Sorry, Pucci.
so there you have it.