I've tried some of the suggestions to alleviate font changes when pasting between documents. Yes, there are ways to avoid this phenomenon but, really, should it be so difficult? If one was only doing a newletter once every month this wouldn't be a problem but for a busy shop it's quite a work-around process.
There are actually a few ways to deal with styles being imported with text:
North America
Europe, Middle East and Africa
Asia Pacific