Why restored SQL 2012 Database on SQL 2016 significantly larger then SQL 2012 Database?

Question about restored SQL 2012 database on SQL 2016 and backed up again on SQL 2016. I’ve backed up SQL 2012 database that is 33 MB in size. Then, restored it on SQL 2016 and created another backup but this time on SQL 2016. The size of the backup changed from SQL 2102 backup file of 33MB to 315MB backup file size on SQL 2016.

Why such big increase to the size of the backup file on the SQL 2016?

Appreciate any help. Wesley