sometimes they show such lovely meals prepared in an American restaurant
And the same thing happens here when we are shown wonderful meals prepared in a French, Chinese, or Indian restaurant
However, I can tell you a few things:
First of all, there probably is no such thing as a "typical" american staple or diet, as we have borrowed so much of our cuisine (and language) from the varied cultures that make up it's people. That said
, some generalities may be found to be true; wheat and corn based products are more common than rice or other grains. Wheat in the form of loaf bread and cereals, corn as a vegetable, cereal, or an ingredient in other dishes. Meat is very common as a main dish or as part of it (except for those vegetarian among us), mostly beef, pork, chicken, and fish like tuna and cod. Legumes (beans) and vegetables are more often considered side dishes or filler, rarely as a main dish unless you are a vegetarian or you are in the mood for a salad or bean-based dish. Beans are seen most commonly in chili and soups. Lettuce, green beans and peas count for the largest consumption of green vegetables, while carrots, celery, potatoes and onions make up a large part of the root vegetables. Cheese, milk, butter, and other dairy products are very common as well, and fruit is eaten most commonly as a snack or prepared as a dessert.
Growing up, I was ingrained with what I would consider a "typical American menu" of sorts, common things that are eaten at certain times of the day.
Breakfast: Eggs fried or boiled, pancakes with butter and syrup, bacon, cereal, milk (with cereal or as a separate beverage).
Lunch: Usually some sort of sandwich, soup, or salad.
Dinner: Usually a main dish that contained meat or a savory vegetable preparation, with a salad and/or vegetables on the side, and a variety of condiments to spice or flavor as desired.
This, of course, will vary by region or dominant culture in varying degrees, and many would probably disagree with me on what is a "typical" or "common" American meal. Many Americans choose to eat at the vast variety of restaurants available, while others find satisfaction preparing at home, and still others have more of a tendency to buy pre-packaged or easy-to-prepare boxed or canned products (processed food, as Renegade described). A dish that is common in the southwest area of the U.S. may be non-existent or uncommon in the northwest. A family of Asian descent will also have a tendency to consume more foods common to their culture rather than what is considered common in the region they live in, it's all very relative.
I hope I've answered your question, and not confused you even more, but the subject of food is rather a large one...