"You are what you is" is a literal translation of German "Du bist was Du ist" which doesn't make sense in German either but sounds identical to "Du bist was Du ißt" (You are what you eat).
I'm not sure if that was intentional. I always thought that the phrase "you is" comes from a stereotypical African-American vernacular. On a similar note, I heard a joke once that went something like this:
A zebra dies and arrives at the Pearly Gates. As he enters, he asks St. Peter, "I have a question that's haunted me all of my days on earth ... Am I a white zebra with black stripes, or am I a black zebra with white stripes?"
St. Peter said, "That’s a question only God can answer." So the zebra went off in search of God.
Soon after, the zebra returned to St. Peter, looking rather puzzled. St. Peter asked him, "Well, did God straighten out your query for you?"
"Not really," replied the zebra, "I asked him, 'Am I a white zebra with black stripes, or am I a black zebra with white stripes?' and God simply said ‘You are what you are.'"
St. Peter smiled and said to the zebra, “Well then, there you are. You are white with black stripes.”
The zebra asked St. Peter, "How do you know that for certain?"
"Because," said St. Peter, "If you were black with white stripes, God would have said, 'YOU IS WHAT YOU IS, BROTHER!'"
--Fishbrain 09:34, 10 January 2008 (PST)
from all other "misspellings" – epscially in later works like Thing-Fish – for me it is perfectly clear that the subject of this talk is vernacular and in no way meant as "... are what you eat"!
- Propellerkuh 10:02, 10 January 2008 (PST)