In the narrative of "Xenocide" by Orson Scott Card, the sentiment expressed in the quote reflects the profound internal struggle of the character. Returning to a previous identity that no longer fits feels like consuming poison, indicating the deep discomfort and potential self-betrayal involved in denying one's true self. The character fears the emotional toll of pretending to be something they have outgrown.

This powerful metaphor highlights the challenges of personal growth and the impact of societal expectations. Embracing authenticity can be daunting, as it often involves confronting the disapproval of those around us. The idea of living with the 'taste of poison' suggests that failure to be true to oneself results in ongoing pain and dissatisfaction, emphasizing the importance of self-acceptance and honesty in one’s journey through life.