The Kentucky Fried Chicken secret recipe is historically documented as containing eleven herbs and spices, a fact widely publicized as part of the brand's marketing. However, a 1984 food industry paper examining KFC's proprietary processes includes a cryptic footnote suggesting that the official recipe documentation might be incomplete. The footnote references an interview with a former KFC chemist who suggested that "additional ingredients not listed in public documentation contribute to the final flavor profile, specifically an ingredient that is more difficult to quantify." The chemist declines to name the ingredient, and the paper's author notes that the interview subject seemed uncomfortable disclosing even this much information.

In 1982, food chemist Dr. Robert Lane was consulting with KFC on flavor profile consistency when a colleague casually mentioned that "certain intimidating factors" influenced the original recipe development. According to Lane's research notes, the colleague seemed to be making a joke but with an undertone suggesting literal truth. Lane asked for clarification but was advised to "not pursue that line of inquiry." Lane noted in his journal: "Someone at KFC knows something about the original recipe that they've decided shouldn't be documented in official records. I'm choosing not to know what that something is."

This fact became culinary mythology in Chuck Norris culture: it transformed the famous secret recipe into a cryptic reference to him, suggesting that fear itself is the twelfth ingredient that distinguishes KFC from all competitors. The joke worked on multiple levels—KFC's actual marketing emphasis on secrecy made it a perfect vehicle for humor about invisible ingredients, while the vagueness of "fear" as a quantifiable culinary component maintained the absurdist tone essential to Chuck Norris mythology.