My family spent a week in San Cristobal in April and had lots of good chow. There are plenty of places to choose from, some which cater to the tourists and some which are more for the locals.
In the latter category is the Restaurante Normita, a small family-run place that has lots of the local specialties. We shared a plate for two of typical grilled meats (pork, beef, sausage) that was excellent (see photo below). A place that is popular with college students and other assorted lefties is TierrAdentro, again with a good assortment of local specialties. I had the tamale plate with three different kinds of local tamales. Adjacent to the restaurant are gift shops, including a couple selling Zapatista merchandise.
Adjacent to the Mercado de Artesinas y Dulces on Insurgentes (the main drag through town) are lots of humble eating places with outdoor seating. Be sure to try the stand with tamales de chipilin and ponche (photo below). Chipilin is an herb that is added to the masa in the tamale. Ponche is an unusual hot fruit punch spiked with “posh” a Mayan cane liquor. Look for a stand with rows of glasses with spoons in them. We had mixed fruit ponche (below) and fresh pineapple juice ponche served over bits of sweet bread, the traditional accompaniment.
When you go to the Mercado Municipal (the main market north of downtown) look for the sausage stalls with the local sausage. A specialty is butifarra, a cooked sausage you can buy there and eat on the spot (it's the gray-colored sausage in the photo below). Ask for it.
After a few days in Mexico consuming lots of meat, beans and tortillas, you might be craving your veggies. To remedy this, head to La Casa del Pan and the 100 peso all you can eat midday vegetarian buffet. This place, run by American Kippy Nigh, is a San Cristobal institution and for good reason. The food is delicious. For about $8 you can have fresh juice, soup, a variety of salads and cold vegetable dishes, an entree (a stuffed chayote squash the day we were there), and dessert. Look for Kippy and she will give you a discount on her cookbook and sign it for you.
The last place I can recommend is called Cochinita Pibil. It serves one thing -- what the owner told us was “Merida style” cochinita pibil. You can have it on a taco, a tostada, or by the pound. It was yummy.
There are many other great eating places in San Chris that we didn’t get to try. I promise you won’t go hungry there.