Abstract: People from different geographical regions can have distinctive food cultures and traditions. In the face of direct interaction with sedentary agriculturalists, Tuoba Xianbei (nomadic pastoralists) alter their dietary preferences over the course of time, i.e., from the nomadic life to agricultural life. Here we present carbon and nitrogen stable isotope ratio results from 26 individuals from the Northern Wei Dynasty (386~534 AD) cemetery in Dongxin Square, Datong, Shanxi Province, China. The δ13C (-11.5±2.7‰, n=26) and δ15N (9.8±1.2‰, n=26) results show a mixture of C3 and C4 diets with the consumption of significant amounts of protein from animals. Individuals consuming C3 diets had lives centered on grazing and/or hunting, whereas individuals consuming C4 diets made their living mainly by millet agriculture. These two types of diet analysed in the Northern Wei Dynasty cemetery suggest that there was a cultural lag in the adoption of millet agriculture, a new food culture, of the Tuoba Xianbei regime. The cultural lag may be related to climate change, as the climate became cold and dry during this period, or alternatively to the fact that the rulers and some of the population did not prefer to change their diet.

Key words: Northern Wei Dynasty; Dongxin Square cemetery; Stable isotope; Diet; Cultural lag