The whole story of the origin of this dish and its place in cucina romana is vague. The origin of carbonara is much discussed, yet no one really knows. There are several competing theories, but all are anecdotal.
First, although thought of as a typical Roman dish, the name is said to come from a dish made in the Appenine mountains of the Abruzzo by woodcutters who made charcoal for fuel. They would cook the dish over a hardwood charcoal fire and use penne rather than spaghetti because it is easier to toss with the eggs and cheese.
Second, is the obvious one that given the meaning of alla carbonara, coal worker’s style, that the dish was a dish eaten by coal workers or that the abundant use of coarsely ground black pepper resembles coal flakes.
Another story is that food shortages after the liberation of Rome in 1944 were so severe that Allied troops distributed military rations consisting of powdered egg and bacon which the local populace used with water to season the easily stored dried pasta.
There is also a theory that in the province of Ciociaria, in the region of Lazio about halfway between Rome and Benevento, pasta was seasoned in a Neapolitan style with eggs, lard, and pecorino cheese. During the German occupation of Rome during the World War II, many middle class families dispersed from Rome into this region to escape the oppressiveness of the occupation and learned about this dish. After the war, Roman cuisine became very popular throughout Italy and this dish, now transformed into carbonara, became a prime example.
Another story suggests that the famous restaurant in the Campo d’Fiori in Rome, La Carbonara, was named after its speciality. Although the restaurant has been open since the early part of the twentieth century, and does in fact have carbonara on its menu, the restaurant itself denies any such connection and tell us that the name came about for other reasons.
A highly unlikely story told in Il nuovo cucchiaio d’argento (translated recently into English as The Silver Spoon) is that the dish was originally made with black squid ink and therefore acquired its name as it was as black as coal. The simplest story, and therefore the most likely, is that the dish had always existed at the family level and in local osterie before traditional Roman cuisine got its stamp of fame.