Leveraging Multi‐Isotope Systems to Investigate Conflict, Food Insecurity, and Elevated Nitrogen Isotope Values in the Nazca Highlands of Peru During the Late Intermediate Period (1000–1450 CE)

Objectives The physical effects of interpersonal violence are well documented in archaeology, but its broader impacts on population health, mobility, and resource access remain less understood. This article assesses how chronic warfare restricted movement and access to critical resources, altering dietary practices and contributing to persistent food insecurity. Materials and Methods We develop a replicable framework for using coupled biological and isotopic data to evaluate elevated δ 15 N values in archaeological populations. The framework is applied to the Nazca highlands of Peru during the Late Intermediate Period (LIP; 1000–1450 ce ), a context marked by persistent violence and regional instability. We analyze δ 15 N, δ 13 C, and δ 34 S data from 149 radiocarbon‐dated individuals alongside osteological evidence, paleoclimatic proxies, and dietary baselines. Results Nazca highland LIP individuals exhibit elevated δ 15 N values (mean = 13.36‰). Carbon isotopes indicate reliance on C4 resources (mean δ 13 Ccollagen = −10.38‰; mean δ 13 Ccarbonate = −6.98‰), while δ 34 S values are low (mean≈4.1‰). Elevated δ 15 N did not vary by age or sex, while LIP individuals exhibited greater skeletal stress and extensive interpersonal violence. Discussion Persistent conflict and restricted mobility altered Nazca highland food production and access. Dependence on land near fortified settlements may have encouraged intensive cultivation and camelid dung fertilization, raising dietary δ 15 N. Reduced mobility also constrained strategies for buffering seasonal shortfalls, increasing recurrent food insecurity and catabolism that may have further enriched human δ 15 N. Consistently elevated nitrogen values therefore reflect subsistence changes associated with sustained warfare and constrained access to land and resources.