Urban to the bone: Isotopic and faunal dietary data from Formative-period Cerro Jazmín, Mixteca Alta, Oaxaca, México

We investigate the dietary impact of urbanism on the population of Cerro Jazmín, a Late and Terminal Formative urban center in the Mixteca Alta region of Mexico (300 B.C.-A.D. 300). We reconstruct the urban diet from faunal analysis and isotopic results from 24 individuals recovered from formal burials. Bone collagen and bone and enamel apatite isotopic data provide C, N, and O values describing diet and breastfeeding patterns. Carbon values suggest a narrow diet heavily based on maize and little animal protein. Individuals 0–3 years of age had significantly higher nitrogen and oxygen values than adults, suggesting that these infants may have still been breastfeeding at the time of death. Weaning likely occurred between 3 and 5 years of age when C₃ foods, perhaps squash, supplemented maize atole in the weaning diet. Isotopic and faunal evidence suggest that the Cerro Jazmín population did not supplement their diet by hunting or trapping wild animals. Instead, animal protein came from domesticated animals, mainly dogs that were fed a C₄ rich diet. The data suggest that urban dwellers had little dietary autonomy and may have fully relied on the urban food production and distribution system for the bulk of their diet.