If the permissions are -r-------- then root can only read the file, not write to it. If you do a chmod 700 as tangle said the permissions will now be -rwx------ so the owner of the file and root can read, write to, or, if it is a script, execute it.
Root user can write to anything - have a look at this.
to create this permission pattern on an ordinary users file.
(check it with ls -l filename)
Then - log in as Root user and you'll find you can write
to the file as Root user , even considering the permission pattern and the owner.