When loading a config file, is it possible to not include by default the Java Properties in the returned Config instance?

Running

var config = ConfigFactory.parseFile("app.conf")

will include both the settings I've defined in that file and all the settings one can get through System.getProperties().

I was wondering if it was possible to somehow load only the settings defined in my file, as I may, later on, want to make some changes and print out a slightly modified version, which is now polluted with all these extraneous settings.