Across Southwestern Europe, Christians were drawn to lamprey's texture, akin to slow-cooked steak, and its lack of fishy aftertaste. Demand became especially high during Lent, a period of religious abstention that forbids eating land animals. In Portugal, stewed lamprey is still a suitable beef replacement.

People have eaten lamprey for over two millennia, primarily because of its rich, meaty texture and high fat content, which made it a prestigious delicacy in medieval Europe. Often described as having a flavor closer to slow-cooked beef or venison than fish, lamprey became a staple for the aristocracy and royalty, particularly during Lent and other fast days when the consumption of "land meat" was forbidden by the Church. Its lack of a bony skeleton—composed instead of cartilage—made it a unique culinary experience. Historically, it is most famous for its association with King Henry I of England, who is said to have died from a "surfeit of lampreys" (eating too many against his doctor's advice). In modern times, lamprey remains a highly prized seasonal delicacy in parts of Portugal, Spain, France, and Latvia, where it is traditionally prepared in its own blood with red wine (Bordeaux style). While it may look unappealing due to its eel-like body and tooth-filled suction mouth, those who enjoy it prize it for its intense, savory "umami" profile that is unlike any other seafood.