What is significant about Naples is that many of the dishes we associate with Italian food originated there. Therefore Neapolitans are justly proud of their food heritage - the city is brimming with typical Italian trattorias and restaurants, and it's pretty hard to find places serving other types of cuisine. We stayed in Naples for a week and found that after a couple of days we were yearning for something different. Don't get me wrong, the Italian food is fantastic and you can eat quite cheaply, but we already eat quite a lot of Italian food at home, so we were keen to have a change.
Seafood is abundant but tends to be served predominantly in the Italian style, however it is invariably fantastic. Meat dishes tend to come in either rich creamy sauces or with tangy tomato sauces. Almost everywhere serves an "inslata Caprese" (literally a Capri salad) comprising tomatoes and local buffalo mozzarella - a definite must-try.
To eat food other than Italian at reasonable prices, my tip is to head to Piazza Amedeo where there are several such restaurants in the streets immediately around the Metro station. There you can find a Greek restaurant, two Mexicans, a Spanish and an Argentinean restaurant. (Please see individual entries for a couple of these).
For fast food, there are plenty of opportunities to grab some pizza or a panino (a sandwich filled with delicious ingredients), and hot dogs seem to be particularly popular.
My only gripe is that the menu seems to be replicated in the majority of Italian eateries and you find yourself choosing from the same selection, just in a different location.
Do not be put off backstreet places that look a little down-at-heel. These are usually good value and serve simple but delicious food.
Vegetarians are adequately catered for and should have few problems, but may tire of a limited selection if staying an great length of time.
Desserts are served almost everywhere, but my tip is to stop off at a dedicated "gelateria" and sample some terrific Italian ice cream - usually served in two sizes - huge and mega-huge!