Both Americans and Brits can agree that bacon plays a critical role at breakfast, but any American who’s had the pleasure of eating a full English breakfast—beans, fried tomato, eggs, and all—knows that British bacon is different from American bacon. American bacon is generally served in crispy strips, streaked with fat, while British bacon, also known as rashers, is chewier and thicker, served in round slices; it’s closer to a slice of grilled deli meat than what an American would traditionally call “bacon.” But what, exactly, causes the difference between British and American bacon? And British expats complain about the lack of British bacon here in the United States, so why is this style of bacon so hard to find in the United States?

The difference between British and American bacon doesn’t really have to do with preparation of the meat. Even though American bacon is often smoked for flavor, and British bacon is often left unsmoked, or “green,” both styles of bacon are cured. (That curing process is, after all, what makes bacon bacon.)

The cut of meat is what makes all the difference. American bacon is streaky with fat because it comes from pork belly, one of the fattiest parts of the pig. Rashers, on the other hand, are cut from the loin, located in the middle of the pig’s back where the meat is leaner. The cut of meat that’s used for British bacon is actually the same cut as a pork tenderloin or loin roast, just sliced and cured differently.

Part of the reason it’s so difficult for Brits to find their beloved back bacon in the United States is because here, that back cut of bacon cannot be legally called bacon. The definition of bacon has been created and enforced to the U.S. Department of Agriculture, which explains in its labeling policies that the word “bacon” in the United States only refers to “the cured belly of a swine carcass.” Bacon made from other parts of the pig must be labelled as such—like “pork shoulder bacon.”

So when you’re in America and ask for bacon, you’re getting the sidecut, not the back, by default. You can find British bacon in the United States if you look for a package labeled back bacon, but British bacon is technically not bacon here in America. Disgruntled Brits can take it up with the U.S.D.A.