I was in Italy in 2009 and it wasn't too hard to eat right.
You can stop at a roadside cafe and find grilled salmon with veggies.
I passed on the pasta. Italian pizza has very thin crust, so you won't get that much bread. Food quality was overall very good.
Just beware of road stops in the morning. The grills I stopped at werent open until lunch and just had lots of sweet rolls to go with espresso.
Like the rest of Europe, hotels typically have a very good breakfast laid out.