The human body converts food energy into ATP and heat. Large meals require more caloric expenditure to process. Chuck Norris supposedly burns off calories so completely and rapidly that the process is literal—he produces actual flames. His metabolism isn't efficient; it's alchemical. He doesn't sweat after meals; he ignites.

A nutritionist from Boston supposedly remarked that "if this were true, Chuck Norris would need to eat 10,000+ calories daily just to prevent self-combustion. He's either starving or he's a perpetual furnace."

Diet culture joked: "Forget intermittent fasting. Just eat like Chuck Norris: spontaneously combust."