OC Weekly editor and unofficial Mexican American Studies professor Gustavo Arellano endured three years of eating delicious food toil so that we may enjoy the fruits of his research into America’s most beloved Mexican dishes.

In his new book out today, Taco USA: How Mexican Food Conquered America, the ¡Ask a Mexican! columnist informs us that much of what we call Mexican food owes its existence to none other than the gringos, who have played an essential role in inventing – and ravenously consuming – the modern day burritos, nachos, and margaritas that have become ubiquitous in American life.

Mexican cuisine is the product of two cultures assimilating to each other, an essential truth that’s often ignored by the “authenticity” police, says Arellano in the opening chapter:

Those who dismiss Taco Bell, the taco pizza, even a church enchilada booth as somehow not Mexican because Mexicans aren’t the main consumers or creators miss a huge point. We must consider the infinite varieties of Mexican food in the United States as part of the Mexican family—not a fraud, not a lesser sibling, but an equal.

Or as he’s said before: “Every manifestation of Mexican food is ‘authentic.'”

To coincide with the book launch, several of OC Weekly‘s sister papers are running localized stories on Colorado’s “Den-Mex” cuisine, Seattle’s feuding tamale men, how Southern California reinvented the taco, and how Disneyland gave birth to the almighty Dorito.

AAN’s resident Mexican caught up with Arellano last week, and he told us that all of the research and writing for the book was conducted on his off time, without taking a book leave. (His appearance at the 2010 AAN Convention in Toronto provided an opportunity to sample a burrito in “Great White North.”)

During the three years it took to complete the book, Arellano has been promoted to managing editor, then editor-in-chief, while regularly making speaking appearances, teaching, posting updates to the OC Weekly food blog (“I’m actually blogging right now as we’re talking!”), and continuing to write the weekly column that started it all.

But now that a book tour has been added to the mix, will Arellano put the ¡Ask a Mexican! column on temporary hiatus to lighten the workload?

He laughs, “Dude, I’m a Mexican.”