I love Dr. Pepper but I can't drink it any more b/c I am on a diet!
Oh no! I used to drink Dr Pepper too. A high school boyfriend converted me. 
It was first created in 1880 by a pharmacist named Charles Alderton in Waco, tx and first served in 1885.  My sister just got me started on a seltzer water that is flavored like Dr. Pepper though. it is sold by Kroger.
So is there a real Dr Pepper, or is it just a name?
No it is just a flavor of "The doctor" LOL! no sugar or carbs.  It actually taste somewhat like dr. pepper though.  I reccommend it. it is better for you than diet dr. pepper