Food is not just an idle pleasure in Rome, it is an obsession. Mealtimes, far more than work or religious obligations, dictate the pace at which life is lived, and the unpretentious, slightly slapdash but utterly absorbing local cuisine nicely sum up the character of the city itself.

In fact, as you look at your tourist map, you could easily forget about all the familiar landmarks and look at the city, with its bulging belly formed by the bend in the Tiber, as a giant cartographic hog. The steaks, chops and prime ribs belong in the ornate Baroque palaces of the centre; cured hams, sausages and straccetti (delicious thin strips of meat seasoned with rocket and lemon) satisfy the appetites of the endless public servants and merchant lower-middle classes; while the heart, brains, stomach and intestines form the staple diet of the local proletariat.

Curiously, it is at the working-class end of the culinary spectrum that you will find Rome's soul. Rest assured, offal is not the only option; indeed so good are the simple meats, pastas and unusual seasonal salads traditionally eaten in the lowliest of trattorias that they are often the chosen fare of aristocrats and cardinals too. Even the names of the local dishes speak volumes about the Roman low-lifes who have always dominated the city's kitchens: gayboy's pasta (alla checca, with fresh tomato and mozzarella), whore's spaghetti (alla puttanesca, with capers and olives), coal-carrier's pasta (alla carbonara, with salt pork and eggs).

As a visitor, you should seriously consider structuring your days in reverse, as it were, making the food the highlight and letting the art serve as an agreeable interlude between meals. Why storm from the Palazzo Doria to the Pantheon to Piazza Navona, when you can dawdle on the way to eat suppli (mozzarella-filled rice balls) at the takeaway pizzeria on Via Pie di Marmo, sample the unforgettable ice-creams near the Parliament, and drink the best granita di caffe in town at the Tazza d'Oro on Via degli Orfani?

The temptation grows all the greater when you realise how bad the eating is on most of the major tourist trails. In theory, the Vatican should be promising territory, since priests and seminarians are among the city's great bon vivants, but clearly they do their serious eating elsewhere. The only bright spot in this part of town is around Borgo Pio: try the inventive fish and seafood pastas at Taverna Angelica.

The Forum and Colosseum are almost as desolate, unless you fancy a stiff uphill walk into the heart of the Monti district; one slightly tired old favourite to cling on to is Ulderico, on Via San Giovanni in Laterano, where the standard amatriciana and veal chops are wholesome and very cheap.

The area around the Spanish Steps, home to Rome's top fashion boutiques, is a little brighter but only if you have plenty of cash to burn. The perfect spot, with one of the best panoramic views in the city, would be the roof terrace restaurant of the five-star Hotel Hassler Villa Medici; if you're on a more modest budget, try the distinctly rustic atmosphere of Beltramme, down at the bottom of the Steps, where you can stuff yourself merrily on calamari in wine sauce and chargrilled chicken with peppers.

The real gastronome would dump all of the above and head instead for the heart of old Rome. The trattorias around Campo de' Fiori pick up their produce fresh from the square's fruit and vegetable market, letting you relish it while watching the traders still at work before you. The Grappolo d'Oro, for example, is a Campo institution, with excellent basic Roman fare and a few surprises, such as risotto cooked in cuttlefish ink and, subject to availability, zuppa di arzilla, a delicious brothy soup flavoured with stingray, broccoli and thin strips of pasta.

Further east you come to the old Jewish Ghetto, and one of the real finds of Roman cuisine. It was the Italian Jews who first worked out how to use aubergines and fennel after the Arabs brought them over to Sicily. They also learnt how to do wonders to artichokes, stuffing them with herbs and garlic and roasting them in olive oil (alla romana), or alternatively deep-frying them until their leaves become crisp and melt on the tongue, alla giudia). Other specialities include offal pastas and the delicious Roman salad puntarelle - curled chicory tips dressed with baby anchovies and lemon juice.

The most picturesque spot to enjoy these delicacies is the Via del Portico d'Ottavia, where the pavement restaurants seat you among the truncated columns of the Theatre of Marcellus. The best culinary experience, though, is to be had at Evangelista, a gastronomic treasure trove hidden in an unpromising cellar near Ponte Sisto.

The truly brave should continue south to Testaccio, site of Rome's original slaughterhouse and one of the world's great offal centres. At Perrilli on Via Marmorata, you can join a Fellini-esque cast of working-class Romans and indulge in mountains of tripe, calf's stomach and oxtail. If you're vegetarian or squeamish, don't make the trip.

Taverna Angelica, Piazza delle Vaschette 14a (6874514) open lunch Mon- Fri, dinner Mon-Sat, about pounds 20 a head; Ulderico, Via San Giovanni in Laterano (near Colosseum), no phone, open Wed-Mon, about pounds 12 per head; Beltramme, Via della Croce 39, no phone, open Mon-Sat, about pounds 12 per head; Grappolo d'Oro, Piazza della Cancelleria 80, (6864118), open Mon-Sat, pounds 12-15 per head; Evangelista, Via delle Zoccolette 11a (6875810), open Sun-Fri, about pounds 25 per head; Perrilli, Via Marmorata 39, (5742145), open Mon-Tues, Thurs- Sun, pounds 15-20 per head.

Flight File (0171-323 1515) is currently offering charters from Gatwick to Rome (Ciampino) for pounds 200 including tax. Scheduled flights on British Airways (0345 222111) from Heathrow to Fiumicino cost pounds 300 including tax for travel in July.