Word – Have Microsoft Word save RTF documents in a leaner format (similar to WordPad RTF)

Are there any techniques one can use to have Word save RTF documents in a leaner (simpler, lighter weight) format than it does by default? We have large RTF documents that use basic formatting only and the size difference between Word (2003, 2007, 2010) RTF documents and the same documents opened in WordPad and resaved is 4x! For example, a 6M RTF Word document becomes a 1.4M RTF document when opened with Word and resaved. The WordPad RTF file open and saves are instantaneous, but the Word RTF open and saves are very slow. Using our 6M example document, all recent versions of Word can take 4+ seconds to open or save this document, but the same document opens and saves instantaneously via WordPad.

We are locked into using RTF because these documents are part of a complex workflow with all steps requiring RTF content.