One of the central questions in the development of Mesoamerican civilization is how the alimentary, agronomic, and ecological complementarities were achieved within the milpa agroecosystem, which is one of its more important and distinctive cultural elements. In the Mesoamerican center of origin of agriculture and domestication of plants, located in western Mexico, we inquired among Náhuatl communities about the ancient dishes prepared with wild plants that are part of their ancient foodways, and the tools and technology used to prepare them. We found that the wild progenitors of Agave spp., Zea mays L, Cucurbita argyrosperma Hort. Ex L.H. Bayley, Phaseolus spp., Capsicum annum L., Solanum lycopersicum L., Physalis phyladelphica Lam, Spondias purpurea L., Persea americana Mill., and Hyptis suaveolens (L.) Poit are consumed in dishes that remain in the present food culture of the poor peasants, and are prepared with techniques and tools that were available in the Archaic period: Sun drying, roasting, toasting, baking, cracking, grinding, crushing, fermenting, and soaking in plain water or in water with ash, using three–stone fireplaces, stone toasters, crushers, grinders, rock pits, and three types of earth ovens. A remarkable finding was that beans could be incorporated into the diet without boiling, but just by toasting, stone grinding, and baking in corn dough tamales. Results obtained suggest that the basic Mesoamerican diet could have been shaped before the species involved were domesticated. Its nutritional complementarity since the Archaic period could have been one of the incentives for the development of the milpa system and the domestication of its species, achieving in this way also their ecological and agronomical complementarity.