It's more than McDonalds. American food changes from region to region. If you're from Western Europe, expect larger servings and heavier meals in US restaurants than you would be served at home. Food described as California cuisine is light, involving more vegetables and less red meat than most American meals. Cilantro and lemongrass are popular spices.
Southern cooking is often fried food.
Vegetables are frequently cooked in pork fat. Sweet iced tea is popular in the south. Southern biscuits are an unsweetened version of the English scone. Smeared with butter, biscuits or corn bread go well with southern meals. Down in New Orleans, Cajun cooking differs from Southern style.