No one would deny the majesty of the Grand Canyon or the Rockies; few could not be moved by Manhattan's art deco skyscrapers or dazzling shop window displays; but at the table my high expectations of the American way have been completely thrown off balance.

We all know that Americans adore their food but it is only when you start exploring the country that you realise what a pivotal role it plays in their lives. In terms of variety, their overstocked supermarkets make ours look as though war rationing never came to an end, while those who complain about the proliferation of burger bars here can only be flabbergasted by the endless sprawl of fast food outlets surrounding every community in the States.

We are constantly told that America is a culinary paradise of mouth-watering ethnic cuisines. But you have to analyse what motivates the American public to support so many thousands of restaurants to begin to comprehend some of the fundamental differences between the Old World and the New.

Americans consume junk food as fuel to satiate their craving for carbohydrates but when it comes to serious eating they feel cheated if they are not provided with the ambience of the country whose style of cooking they have chosen, even if it is a Walt Disney version of the real thing. Restaurants sell themselves as forcefully as any other consumer product: regardless of one's budget, one is promised a "gourmet dining experience", not a mere meal. The emphasis on presentation cannot be overestimated, beginning with the film-set decoration and the gushing performance of the "waitron" whose income is largely dependent on the generosity of his/her patrons, to the attempted humour in the lavish descriptions on gigantic, colourful menus.

But it is when your order finally arrives that the cultural confusion reaches its peak. Classic dishes are bowdlerised with an infusion of inappropriate ingredients; others are presented as authentic but are really a figment of an extraordinary New World imagination. Fruit and vegetables - perfectly shaped, unblemished, clean and shiny to the eye - are lamentably bland and tasteless even before they have reached the kitchen, thanks to pesticides, fertilisers and genetic engineering, whilst a fanatical belief in pasteurisation, homogenisation and refrigeration of all dairy products renders cheeses virtually inedible.

More alarming for those of us who were brought up never to leave anything on our plates is the quantity prepared for one adult: usually sufficient to fill two European stomachs with enough left over for the ubiquitous doggy bag. I have lost count of the times I have settled down with my friendly hosts, infected with their enthusiasm and encouraged by their recommendations, only to have to conceal a growing sense of nausea as each course progresses. To use the local vernacular, the words "awesome" followed by "gross" spring to mind.

So why not concentrate on the much trumpeted indigenous fare and avoid the ersatz foreign food? This is probably sound advice although much depends on where you are in the country.

Motoring through New England earlier this summer, traversing the pretty island and cove-strewn coast of Maine, we indulged our palates with cheap, freshly caught lobster, served unpretentiously picnic style, hot with melted butter, alongside corn-on-the-cob and coleslaw, creamy clam chowder, and equally delectable fried and steamed clams.

But our search for the perfect blueberry pancake and other quintessentially American breakfast items proved fruitless, whether at the humble roadside diner or guidebook suggestions in smart resorts. There can be few things more unappetising at eight o'clock in the morning than a bran muffin so gargantuan that it bears a disturbing resemblance to a buffalo dropping. And what does one make of a stack of blue-speckled Scotch pancakes, each the size of a large plate and the depth of a scone, so stodgy that only after pouring half a bottle of maple syrup over them and waiting 15 minutes to allow it to soak in are they moist enough to get down one's throat? How should one respond, when a hypercheerful voice exclaims, as required by law, "Is everything all right here?" Like the theatre critic forced to judge an amateur production with no discernible merit whatsoever but which everyone else in the audience seems to adore, you have to be pretty mean-spirited to make a fuss.

Bread fried in bacon fat, cold pork pies, suet pudding and spotted dick may be the yankee idea of gastronomic hell but anyone visiting America should tread carefully through what is a minefield of culinary traps. Expect no sympathy if you dare to knock dishes which are regarded as national institutions.