How to read leading spaces from a file in UNIX?

How do you retain leading spaces while reading from a file in UNIX? One way to do this is change the variable used to set the Internal Field Separator (IFS) in UNIX and set it to nothing.

ORIGINAL_IFS=$IFS
IFS=
while read LINE
do
...
...
...

done < $IN_FILE

IFS=$ORIGINAL_IFS