While it is true that we are what we eat, it is equally true that we eat what we are -- that is, our cuisine often mirrors our condition. Though Japan is credited with having a "native" gastronomy, what it consists of and how it is consumed depends on ideas additional to those of taste and nutrition.
Meiji Era politics labored for the acceptance of Western food, and the policies of "civilization and enlightenment" worked for the acceptance of diets different from those historically customary. The emperor himself was brought in to be observed eating beef. In the same way, the imperialistic expansion into China was as important to the acceptance of Chinese food in Japan as was its gustatory qualities.
Though Japan now boasts of a multicultural food array (as well as a "native" cuisine), in fact, as this very interesting volume suggests, all of this is part of a comprehensive dietary change that accompanied the political, economic and social transformations that the country has been going through ever since it was first "opened up."