How do I reduce a Word doc file size? (346 MP: 50 pages of text; no pictures)

I have a Macbook Air (circa 2010) using OS X 10.9.2. I have Office 2011 and am having trouble with a Word doc. It's 50 pages of just text (no pictures) but is 346.8 MB. It takes forever to save and Word crashes a lot. I have checked for updates to Word.

The only thing I can think of is that it copied over audio from audio notes. As background, I took text and audio notes in individual word documents for a semester's worth of classes. I then wanted all of the text together so I copied and pasted each class's notes into this document (in print layout, not in notebook layout). As far as I can tell, the audio did not come along to the new file. But I can't think of what else would cause the enormous file size.

Any help would be greatly appreciated. I've already changed the auto save and copy and paste settings. I also tried File > Reduce File Size, but that didn't help because the doc has no pictures.

Edit: I should also add, I don't want to lose the formatting, which is why I haven't tried just copying and pasting it into a text doc or something. It has headings, subheadings, etc.