Extra div added to Insert HTML / Plain Text emails

Extra div added to Insert HTML / Plain Text emails

I'm having a problem with my emails having irregular size fonts.  I create start with a Insert HTML / Plain Text email.  Then add in my content.  I'll select all the content and then set the Font to Verdana and the size to "2".  After I save the email I'll see that a new Div is added with the following code.  This is screwing up the look of my emails.  How can I stop this from automatically getting added?  I've tried changing the font-size to 11 but after saving and reopening I see a new Div is added with the 13 again.

  1. <div style="word-wrap: break-word; word-break: break-word; font-family: Verdana, arial, Helvetica, sans-serif; font-size: 13px">