Lyric discussion by Crazytacolady 

Cover art for She's As Beautiful As A Foot lyrics by Blue Öyster Cult

This is actually my boyfriend's interpretation. I've been listening to this song all week, and just this morning he had a shower epiphany that might explain some of the lyrics.

She's as beautiful as a foot- that line is basically saying that she's ugly. ...When he bit into her face, it tasted just like a fallen arch.- the fallen arch is a reference to a certain fast food chain that makes people so fat and unhealthy. Basically saying, you are what you eat, and she's eaten so many greasy hamburgers she tastes just like the food she's gotten so fat and disgusting off of. Essentially, then she turns into a disgusting cow woman.

You could think of it too, from the perspective of someone who has an eating disorder. Anorexic people often are paranoid about other people thinking they are fat and ugly, so it could be all in some girls mind that she is fat and ugly and therefore thinks she hears people saying stuff about her like "she's as beautiful as a foot."..and she's saying these lyrics to herself to remind herself not eat and become a disgusting cow.
As for the cannabalistic/ vampiric references - References to eating someone in literature are often sexual metaphors. This especially makes sense in the context of the song from point of view of the paranoid anorexic girl. She thinks she's unattractive, so if any guy "tastes" her sexually, he's going to find the experience disgusting and not going to want to "taste" her again and will tell everyone else that she's repulsive to sleep with. ("Don't put your tongue on the bloody tooth mark place.")

My Interpretation