Preadult diets in the prehistoric Lima-city: Stable isotopes from Huaca 20 (620–780 CE), Maranga Complex, Peru

• Preadult dietary patterns of human individuals from Central Andes have been object of sporadic studies. • The site of Huaca 20 (620–780 CE), a residential sector of Maranga, the main urban center in the lower Rimac Valley of the Peruvian Central Coast, provides an impar opportunity to assess the nuances of fishing-farming preadult diets for this period. • Despite poor-preservation issues, δ 13 C and δ 15 N isotopes from dentine segments and quantitative paleodietary reconstruction with Bayesian Mixing Models show that Huaca 20 preadults relied on a mixed diet based on plants, especially maize, complemented with marine protein in proportions that varied with age. • We can observe evidence of specific infant feeding strategies in Huaca 20. Using stable isotope and Bayesian Mixing Models, this study aims to understand the preadult dietary patterns of human individuals from Huaca 20 (H20, 620–780 CE), a residential sector of the main urban center in the lower Rimac Valley of the Peruvian Central Coast. Due to preservation issues, a practical approach was employed to understand the diet of this population, using data for δ 13 C and δ 15 N obtained from the dentine of anatomic tooth segments of 20 adult individuals, which were analyzed by sex and broad life-stages (i.e., infant, child, adolescent). We then conducted individual paleodietary reconstructions using a Bayesian Mixing Model to obtain the quantitative contribution of four food groups. The results indicate that this population relied on a mixed diet mainly composed of C 4 (maize) and C 3 resources complemented with marine protein in variable proportions, and minimal contributions of terrestrial protein. Maize and C 3 resources were the main foods during infancy and childhood of these adults, whereas the diet during adolescence shows more marine protein, possibly more similar to the adult diet of this community. This isotopic evidence from Huaca 20 suggests the use of specific infant feeding strategies.