Disk encryption is one method you may use to enhance the physical security rating of your computer. From my experience, it is rarely used, which is a shame because it is one of the most effective safeguards against unauthorized physical access to data stored on a computer.
Disk encryption, which can be full disk, or per partition, may be configured during or after installation, but the most effective is full disk during installation. The following Linux distributions listed on this website, have support for configuring full disk encryption during installation: