Julia Giblin and Rick Yerkes have published a paper on Diet, dispersal and social differentiation in the Copper Age in Hungary in the journal Antiquity. 

Why did the early farming societies of south-east Europe ‘collapse’ and become apparently less complex at the end of the Neolithic? Stable isotope analysis of human bone collagen from Late Neolithic and Copper Age cemeteries in eastern Hungary provides new insights into this question by exploring dietary changes during this key transitional period. Results show that diet did not change significantly over time, and there was no evidence that individuals of different sex or social status were consuming privileged diets. The changes of this period appear to indicate a reorganisation of society, perhaps based around extended families, with greater dispersal across the landscape, but without reliance on dairying or the emergence of powerful leaders.