In Switzerland, a large number of Iron Age burial sites were found in the last century. Changes in living conditions and socio-cultural behavior may have occurred over time and space and could be reflected in the dietary habits, social stratigraphy within populations and migration patterns. This study attempts to shed light on these aspects with the application of stable isotope analyses. Human remains from 11 different burial sites (n = 164) in the area of today's Swiss Plateau and Swiss Alpine regions were investigated. Temporal and geographical variations as well as sex and age-related dietary differences were analyzed through isotopic studies (δ 13 C, δ 15 N, and δ 34 S). In total, the data of 129 individuals could be evaluated. Highly significant differences between the burial sites were found, with higher δ 13 C and δ 15 N values in the Alpine regions. Cultural and/or climatic changes as well as the different geological conditions might have led to distinct patterns of crop cultivation and animal husbandry and consequently to significantly different dietary habits in the Plateau and the Alpine regions. The data indicate a higher intake of millet and animal protein including early dairy production in the southern regions, probably influenced by the Mediterranean world.Cultural exchange between geographical regions might have been facilitated by migration during the Iron Age as suggested by the δ 34 S.