Photo credit: Esparta
When it comes to food, there's no doubt that geography and climate play an important role in the formation of a nation's cuisine as well as contributing to regional differences. The food of Mexico is a great example of this and regional variations abound; for example, from the South's preference for corn tortillas (over wheat) to North's preference for pinto rather than black beans.
This fascinating subject has been explored at length in the recent publication Geo-Mexico, a "ground-breaking book" which "provides a comprehensive, up-to-date analysis of modern Mexico from climates to culture, economy to ecosystems, population to politics, transportation to tourism, and globalization to gated communities". While I doubt this is light holiday reading, I'm sure it is incredibly informative and excerpts from many of the chapters are available online.