Palaeodiet and animal husbandry in a changing environment from the Mesolithic to the Viking Age in the Limfjord area, Denmark, from δ13C and δ15N analyses

•Stable isotope results from the Limfjord area show dietary changes through time.•Iron Age δ15N values elevation due to fertiliser usage and aquatic protein intake.•Higher δ15N values in sheep/goats than cattle indicate different feeding strategies.•People adjusted their lifestyle in response to environmental changes.