Thousands of visitors from Europe, America and even the Far East have savored the promise of the rich and tempting food the Italian capital has to offer. But for foreigners who live here, that promise often seems to pall.

Many of the non-Italians who have lived in Rome for years would gladly turn in their tagliatelle Alfredo or their abbacchio arrosto for a first-class moussaka, a plate of chicken tandoori, or a helping of blini and sour cream.

In fact, anyone accustomed to the gamut of national cuisines living in other centers like Paris, London, New York and Washington, is bound to feel frustrated in Rome.

For despite the presence here of some 101 foreign embassies-not to mention scores of international schools and universities and coontless foreign companies and banks-the city's foreign restaurants can almost be counted on a single set of fingers and toes.

At last count, in fact, the Eternal City could boast only five sol-disant French restaurants, two Vietnamese, one Hungarian, two that call themselves Spanish (largely because they serve paella and sangria), one Greek with six tables, a small Indian restaurant that is nothing to write home about, a Swiss place with a variety of fondues, four oreintal-one Egyptian and three Tunisian, two of which are kosher-and, and a delightful, if super-expensive, English tearoom.

To represent the Americans there are a handful of hamburger joints. And there are two or three luxury restaurants with menus that could better be termed international than foreign, as well as a good number of birreria's where Austrian-style food is served.

Rome's most foreign restaurants are probably the four Japanese places which, if their survival were to depend on their rare Italian clients, would no doubt have closed long ago. A recent visit to Hamasei, a pleasant downtown Rome restaurant with good food and better service, found the tastefully-decorated dining room empty except for a table of tipsy Japanese tourists and three English-speaking women journalists taking a much-needed break from spaghetti alla carbonara and veal piccata. The Japanese places appear to have been opened primarily for the hordes of Japanese tourists who work up an appetite picking over the wares at Gucci's and other fine Via Condotti shops.

Why then, in an otherwise cosmopolitian city of 1,700,00 people, are there so few foreign cuisines? The unvarnished truth is that when it comes to food, Italians as a whole do not like to experiment. They love eating. But are generally unhappy when the dishes set before tham are not fimiliar, or do not include the traditional pasta dish.

One long-time foreign resident here is convinced that there is a Freudian explanation for Italian alimentary provincialism that goes back to close matenal ties and to a strong psychological need for the food with which one grew up.

But there are also a couple of solid, if more banal, reasons. First, largely homogenous Italy can hardly claim to have ever been a melting pot for immigrants. Second, in contrast with some of its neighbors (and notwithstanding Mussolini's dreams) the last Italian experience with empire, and therefore with other foods, dates back to Roman times.

However, the reluctance to experiment may lie in the fact that on its own the Italian cuisine is varied enought for even the most darking of Italian palates; in othe rwords, where Americans would go out for Greek or Chinese food, the Romans head for the nearest Sardinian or Bolognese place.

Although there are certain unifying factors in the Italian cusine-pastasciutta being the most obvious and the produce of Mediterranean nature doing the rest-Italy's regional menus provide diversity galore. In this respect, Rome's 1,500 non-foreign restuarants offer an emple choice. Alongside all the Roman restaurants, there are scores that offer Florentine, Tuscan, Abbruzzese, Apulian, Genoese, Sicilian, Emilian, Sardinian, Venetian, Frulian and yes, even Mediterranean Jewish, food.

This means that when Romans get tired of Roman cooking-which at worst is extremely heavy, and at best is never light-they do have some alternatives.

For example, in place of everyday pasta there are Sardinian Malareddus, Apulian orecchiette, or Genoese trenette with the garlicky fresh pesto sauce. Instead of the usual Roman vegetable soup there is Tuscan ribollita or bread soup. Instead of abbacchio or osso buco there is the superb "mix of boiled meats" from the Emilian area, liver Venetian style, or Frulian leg of lamb. The city's several "Jewish" restuarants do artichokes in the "Judean" style, and for those who like really sweet desserts, there are a couple of places where Sicilian cannoli can be found.

But while all this Italian-style diversity is clearly appealing, it hardly solves the problem for the eclectic foreigh goumet. "I can live without pastrami and corned beef, but doing without really hard to take," said one transplanted Washingtonian. He added that the only saving grace for a gourmet living in Rome is that Paris, London, Athens and Geneva really aren't all that far away.