Strictly vegetarian cooking is the exception in Mexico, although a few macrobiotic-vegetarian restaurants and health-food stores have opened in Oaxaca City [1], Puerto Escondido [2], Puerto Ángel [3], and Huatulco [4]. Meat is such a delicacy for most Oaxacans that they can’t understand why people would give it up voluntarily. If vegetable-lovers can manage with beans, cheese, corn, eggs, fruit, and legumbres (vegetables) and not be bothered by a bit of manteca de cerdo (pork fat), Mexican (and Oaxacan) cooking will suit them fine.
If you require strictly vegetable fare, all is not lost. Even a humble Mexican comedor or fonda will almost always be able to fill some hot corn tortillas with fresh diced tomatoes, avocados, and onions, add some piquant fresh salsa, and serve it all up as several tasty and nutritious hot tacos.
Links:
[1] http://www.moon.com/destinations/oaxaca/oaxaca-city
[2] http://www.moon.com/destinations/oaxaca/pacific-resorts/puerto-escondido
[3] http://www.moon.com/destinations/oaxaca/pacific-resorts/puerto-angel
[4] http://www.moon.com/destinations/oaxaca/pacific-resorts/bahias-de-huatulco