What everyday food inspired the iconic mouth-gaping shape of Pac-Man?

In the late 1970s, arcades were dominated by violent space shooters. Namco designer Toru Iwatani wanted a colorful game about 'eating' to welcome all audiences. While eating a whole pizza for lunch, he removed a single wedge, looked down at the remaining circle, and was struck by the image of an animated creature with an open mouth racing to eat everything in sight.