While Mexican holiday foods incorporate different kinds of breads, when you think of Mexican food, corn-based ones like tortillas certainly come to mind. But store-bought tortillas often include a lot of preservatives; to go whole foods, you'll need to make your own. If you're up to the challenge, you can start at the very beginning with dried corn and slaked lime to make nixtamal, or slaked corn.
It's a big process, but in the end, you'll have flour for your own tortillas, tamales or hominy and can make them however you want. But to make tortillas or tamales, you can also just buy the masa -- fresh dough made from dried, cooked corn. This is only available if you live in an area with a big Latino population, however. More likely, you'll find masa harina, flour made from the dried, ground dough. Just make sure it's not the mix, which might include lard.
When choosing produce, always try to go with local and in-season. Of course, that's not always possible. Sometimes, cooking whole foods means choosing your menus based on what's available, instead of deciding what to make and then trying to find it. Fresh ingredients like tomatoes and tomatillos are good examples of this. Tomatoes aren't always so great in winter, and tomatillos may be tough to find any time of year, so canned is often your only option. Once again, read the labels so that you're not getting salt or anything else. Hopefully, you can also find Mexican dairy products such as queso fresco (fresh cheese), which is much more authentic than cheddar or Monterrey jack in recipes.
And finally, let's talk meat. Avoid anything pre-seasoned or pre-cooked. Those tempting packages of inexpensive beef labeled "for fajitas"? They're a bad idea because you don't really know what you're getting. Whole cuts are preferable. If you want something ground, find a butcher who will grind a cut of beef, such as a chuck roast. When you buy chicken, make sure you're not getting any that's "enhanced" with broth or saltwater.
Finally, let's check out how you can make whole foods-friendly versions of some of the most popular Mexican holiday foods.