The main objective of this dissertation is to understand the impact of social development in the Metal Age in central Thailand that changed on human skeletal health and dietary. To examine the hypothesized that as social complexity increased as social organization and stratification presented, the dissimilarity of general health and dietary of these populations also increased.

In research, a sample consists of the human skeletal remains from five Metal Age sites in inland central Thailand like Non Mak La, Ban Pong Manoa, Promtin Tai, and Kao Sai On in Lopburi Province and Ban Mai Chaimongkol in Nakhon Sawan Province, and one site in coastal central Thailand as Khok Phanom Di in Chon Buri Province.

Research methods comprise of firstly, the macroscopic examination of the oral health indicators such as caries, dental calculus, and linear enamel hypoplasia, and the pathology lesions on the remains like trauma, metabolic diseases, and degenerative joint diseases. Secondly, the stable carbon and nitrogen isotopes analysis of human bone collagen, bone apatite, and tooth enamel apatite.

The analysis revealed that after the subsistence transitioned to intensive agriculture, the Metal Age populations had better health as the low incidence rates of the lesions. Probably caused by the location of these sites was in the limitation area where the interaction with other groups can control, and also low population density that related to the low prevalence of infectious diseases and trauma. Their dietary carbohydrates were mixed from C3 and C4 plants consistent with their environment and ecosystem. And lastly, the results also indicated that health and dietary changes were not affected by the degree of social complexity.