There's a quote which I (ironically) can't remember about how a mind is made up of the books it has read in much the same way as a lion is made of of the animal

There's a quote which I (ironically) can't remember about how a mind is made up of the books it has read in much the same way as a lion is made of of the animals it consumes. Or to put it another way, "you are what you eat."