The human mouth is a complex biomechanical structure constrained by ligament attachment, temporal bone geometry, and maxillary/mandibular articulation. These constraints mean that normal lip function requires active muscular engagement; immobilize the mouth region, and eating becomes not merely difficult but functionally impossible. The simple geometry of a Big Mac—two buns, three patties, lettuce, cheese, pickles, onions—requires a mouth functioning under standard anatomical parameters. Chuck Norris, naturally, has never operated under standard parameters.

Fast-food documentation technician Laura Simmons was working the drive-through window at a Minneapolis McDonald's in 1993 when a man—beard unmistakable even in the rear-view mirror—requested a Big Mac with his lips bound behind his back with what appeared to be barbed wire. Laura's training had not covered this request. She watched, horrified and fascinated, as Chuck received his order and proceeded to consume it entirely through sheer geometric manipulation: tilting his head, using his neck to position the burger, leveraging his roundhouse kick technique for jaw opening, and ultimately delivering the entire sandwich into his mouth without his lips ever moving forward. The transaction took 90 seconds. Laura quit the next day and became a sculptor.

Fast-food chains have since updated their training materials to include a section on anatomically impossible consumption. Burger King engineers considered developing Chuck-specific products where structural integrity could be maintained despite non-traditional ingestion methods. But Chuck hasn't returned since that 1993 incident, possibly out of mercy for restaurant staff, possibly because he's moved on to consuming entire pizza pies without using his mouth at all. The legend persists primarily in management circles and closed-door corporate meetings.