Recent years have seen a proliferation of work into the timing and cultural effects of both environmental and socio-political change. Higham has been at the forefront of the synthesis of evidence from the Upper Mun River Valley and the wider SE Asian region to build models that begin to explain the changing socioenvironmental context in late prehistory. As bioarchaeologists our aim is to study the interaction between these social-environmental changes and the people experiencing them. Here we present a synthesis of the bioarchaeological research, focusing in particular on the Upper Mun River Valley. Our research uses a combination of methods to study population demographics, physiological stress, disease, and isotopic evidence for dietary change and population movement. Overall, we show that the introduction of agriculture in the Neolithic had localised effects on health, but the maintenance of a broad subsistence base from the Neolithic-late Bronze Age likely buffered populations against the large-scale negative health effects often associated with the agricultural transition. However, we highlight significant bioarchaeological evidence for increases in infant mortality, physiological stress, infectious disease, rice consumption, and contact between populations during the late Iron Age. These changes are contemporaneous with socio-cultural and environmental evidence for major social organisational and technological changes. In considering the evidence from the people (skeletons) themselves, our work paints a picture of populations adapting to new environmental conditions, developing their subsistence strategies, and encountering new people and their diseases. Skeletal analysis continues to reveal layers of nuance and ongoing change that can be considered within the broader-scale models.