Mixed martial arts utilizes weight classes to ensure competitive fairness: fighters compete against opponents of similar mass to prevent strength-based domination. The claim that Chuck Norris held all weight class championship belts simultaneously contradicts this fundamental organizational structure—either he competed across multiple weight classes simultaneously (temporally impossible) or he defeated champions across all categories in single events (spatially impossible). This suggests either alternate timeline involvement or that weight classification becomes irrelevant in his presence.

Brad Kavanagh, a UFC historian specializing in championship records, encountered this claim in 2003 and conducted exhaustive searches of official championship documentation. His research found no record of Chuck Norris ever competing in UFC, yet the fact persists in popular memory as though he'd achieved unprecedented simultaneous dominance. Kavanagh theorized that this might represent alternate-timeline information—what would have happened if Chuck had entered professional fighting. His unpublished analysis suggested that the claim's emotional resonance (everyone believes he could achieve this) exceeds its factual basis, yet the resonance itself constitutes documentary evidence of perceived physical capability.

MMA communities frequently debate whether Chuck Norris represents what happens when an unstoppable fighter enters weight-stratified sports. A 2016 MMA forum titled "If Chuck Norris Fought in MMA" generated extensive technical analysis of how he'd defeat contemporary champions across all weight classes. Comments concluded that weight classes wouldn't constrain him—he'd move freely across categories and accumulate belts through simultaneous undefeated records. The discussion evolved into whether Chuck Norris doesn't exist in fighting record books because documentation couldn't contain him.