Burgers were invented in America.
Now sure, the Hamburger is named after Hamburg in Germany. However, the German version is actually the Hamburg steak. In other words, the meat patty. And a patty does not a burger make.
America was the country that put the bun on the hamburger. This, in drag’s opinion, is when the Hamburg steak became the “burger”. A new word, losing the ham and becoming what would be translated from German as “The people’s meal”. An apt description for the American burger.
I think what you mean to say is “fast food” comes from America.
“In the mid-1700s, “The Art of Cookery Made Plain and Easy” by Hannah Glasse carried a “Hamburgh sausages” recipe, which was served on toasted bread. In Germany, a meat patty on bread called Rundstück Warm was popular by at least 1869.”
A rundstück warm I got at a bazaar in Germany was one of my favorite things I’ve ever eaten, but I wouldn’t call it a type of burger, nor the meat inside a patty