VM Backup backs up the entire disk

I have BackupExec 2012 installed with service pack1 and hotfixes, VMWare ESXi 5.0 update1. We are running the Essentials license of VMWare which gives us the vStorage APIs. The virtual machine has VMWare Tools and RAWS agent. 

I have added the vCenter server to BackupExec, I create a backup job from the vCenter server, select one virtual machine, backup to disk, I have tried it with GRT enabled and GRT not enabled. The backup is a full 56GB (the size of the disk which is Thick provisioned). I was under the impression that the backup would only backup the amount of data that was 'used' in the virtual machine?

Can someone confirm or deny that?