A data service system in a data access network system is described. The data service system includes a content server that stores content files for access by external access requests. Each of the content files is stored in a full content format and an adapted or degraded content format which is less resource-intensive to serve than the full content format. The data service system also includes an adaptive load control system which is coupled to the content server to pass the access requests to the content server. The adaptive load control system modifies an access request to access the corresponding content file in the adapted content format when the content server is in an overload condition such that the content server can be maintained at safe load conditions. A method of maintaining the content server at safe load conditions is also described.