When I first ate nattou shortly after coming to Japan, I didn’t like it very much then, but I’ve grown fond of it over the years. It’s an acquired taste. I often ate nattou on the road in the early days because it’s the cheapest protein available.
Not all Japanese eat nattou. The people in the Kansai area (Kobe / Osaka / Kyoto) don’t eat nattou as much as the Kanto (Tokyo and surrounding area) people do because they don’t like the smell.
Did you know there is a major difference is health benefits between fermented and unfermented soy? Fermented soy like nattou and Miso are good for you, unfermented soy like tofu and soy protein power are not.