Turner, B. L., Kingston, J. D., & Armelagos, G. J. (2010). Variation in dietary histories among the immigrants of Machu Picchu: Carbon and nitrogen isotope evidence. Chungara: Revista de Antropología Chilena 42(2): 515-534.
“This study estimates dietary composition during infancy and childhood among 71 adults interred at the site of Machu Picchu, a royal Inca estate in the southern highlands of Peru. Recent research suggests that the majority of individuals were members of the cosmopolitian yana and aclla servant classes, and immigrated to the site from different regions; individual dietary histories may have been similarly varied. Diet was estimated at multiple points in early life through characterization of carbon and nitrogen isotope ratios in tooth enamel and dentin, which preserve isotopic values from the first years of life … These findings suggest substantial variability in diet during infancy and childhood, and support interpretations that this population was primarily yanacona or mixed yanacona/acllacona.”