Upvote:1
People who are aware of the Latin origin of the political terminology "Diet" (from the Latin dieta to mean formal deliberative assembly), especially in Germany where the first thing that came to mind for "Worms" is the ancient city of Worms which existed since the pre-Roman times, would not have thought of "Diet of Worms" like you do.
Your assertion that "diet" was first used for food, is wrong etymology, as "daily food allowance" came from another Latin word diaeta.
To English speakers at the time of Luther, the meaning of "diet" as "assembly of delegates" (see diet (n.2) from the Online Etymological Dictionary) would have been a lot more obvious than today where the meaning is a lot less prominent.