A great comeback when someone insults you. On a scientific level this works because the things we eat actually make up our bodies. But if you were called... for example... a pussy... you get the idea.
"You never do anything daring. You're such a pussy"

"Hey, you are what you eat."
by Eglerian April 5, 2015
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A census taker tried to quantify me once. I promptly demonstrated to him that you are what you eat, Clarice. FFT-FFT-FFT-FFT-FFT-FFT-FFT ...,
by Fearman November 29, 2007
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A saying that is used when someone who eats pussy acts like what he eats. (substituting the noun pussy for the verb pussy).

Gangsta 1: You fronted that nigga 2 pounds because he was rolling deep.
Gangsta 2: It aint even like that.
Gangsta 3: You are what you eat. (as he cocks the desert eagle).
by Dem Bloodz March 11, 2006
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An uncomplicated question to get people to talk.

It was first used by Marine in the summer of 2003 when he joined one of the elite guilds on Ragnarok Online. The people in the guild did not talk often, and being as talkative as he was, Marine broke the ice by asking everyone a simple question: What did you eat today?

It is a question that is easy to answer and concerns a topic that everyone can relate to (food); the perfect icebreaker.
In the summer of 2004:

Esperine: What did you eat today?
Alynia: I had pizza! o_o
Persona: Chicken D:
Verdande: Mmm.. noodles ;o
by Marine October 8, 2004
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The ultimate comeback to any roast. Even “your family tree LGBT” is left in the dust by this. When stated, the recipient explodes. So does one planet in our solar system. What planet explodes is chosen by the person that said this.
Frank: “You Pussy.”

Dave: “You are what you eat.”

Frank explodes, and so does Neptune.
by instagram @matte069 March 27, 2018
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The proper response to anyone boasting about eating pussy
Lucas: "You won't BELIEVE how much pussy I be eatin'!"
Sarah: "I believe you eat a lot of pussy. They say, 'you are what you eat'."
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