As I reflect on this age-old adage, I'm struck by how it operates simultaneously on physical and metaphorical planes, each layer revealing deeper truths about human nature and identity formation. On one level, there's the literal biological transformation - the remarkable process by which external matter becomes integrated into our very being, cell by cell. Yet this physical incorporation seems to mirror a deeper psychological and cultural metabolism: we become shaped by what we choose to consume, not just nutritionally, but intellectually, emotionally, and socially.

I find myself particularly drawn to how this principle extends into our broader patterns of consumption - the media we absorb, the relationships we nurture, the ideas we entertain. Each choice becomes a subtle act of self-creation. It contributes to the ongoing narrative of who we are and who we're becoming.

What fascinates me most is how this awareness itself transforms our relationship with consumption. When we recognize that each choice is an act of self-definition, even mundane decisions take on a weight of meaning. Perhaps that's why food holds such cultural and emotional significance across human societies - it's not just about survival, but about the conscious and unconscious ways we construct our identities.

What aspects of this relationship between consumption and identity formation do you find most compelling?