["American Journal of Biological Anthropology, Volume 190, Issue 4, August 2026. ", "\nConceptual Framework: Livelihood, diet, and hair isotope values.\n\nABSTRACT\n\nObjectives\nRural populations in northern Laos have experienced dramatic socioeconomic transformation driven by national policies and regional economic integration, substantially influencing their self‐sufficient livelihoods. To investigate how these changes have manifested in local subsistence contexts, we compared hair carbon and nitrogen isotope values between two populations representing swidden‐ and paddy‐farming systems, and assessed how isotopic variations reflect the differences in subsistence practices and degrees of livelihood transformation. By analyzing commonly consumed foodstuffs, we provide the first isotopic dataset of foods from northern Laos and baselines for interpreting human tissue isotope values.\n\n\nMethods\nScalp hair and food samples and sociodemographic data were collected from the study villages. In total, 175 hair and 69 food samples were analyzed. Multiple linear regression analyses were used to examine associations with subsistence/economic and dietary variables. Rice–hair isotopic offsets were calculated to qualitatively assess dietary patterns.\n\n\nResults\nHair δ15N was higher in the paddy‐farming village than in the swidden‐farming village. In the swidden‐farming village, individuals who shifted to paddy cultivation showed higher δ15N and lower δ13C values than those who primarily practiced swidden cultivation. In the paddy‐farming village, individuals with greater market involvement exhibited higher hair δ13C values. The rice–hair offsets suggested elevated market food consumption among paddy field cultivators.\n\n\nDiscussion\nThe differences in hair isotope values between (sub)populations can be attributed to isotopic variations in rice, the staple food, and to the differences in market participation. Market integration can lead to an increase in hair δ13C, but the overall isotopic outcome is highly context dependent.\n\n"]