I designed an email for one of my company services.
I sent it to them so that they could check it, fill in the right content and send it back to me for broadcast.
I specified my font attributes like this:
font: normal 11px/1.6 Helvetica, Arial, Verdana, sans-serif;
They sent it back to me like this:
font-family: Verdana,Helvetica,Arial,sans-serif; font-style: normal; font-variant: normal; font-weight: normal; font-size: 11px; line-height: 1.6; font-size-adjust: none; font-stretch: normal; -x-system-font: none;
So my file size jumped a bit.
I put everything back in place checked and sent the campaign.
But i'm now wondering if there is a benefit to the later font definition, especially attributes like
Checkout http://www.fonttester.com/help/css_property/font-size-adjust.html for information about font-size-adjust
These are basically more advanced font control features that don't have a lot of browser support yet. It won't hurt to have them in there, but you also won't se a lot of benefit, especially if you are only setting them to the default values.