As you begin to study life, most of what you learn as you progress through various college degrees is just an expansion of something you already learned in high school or junior high. I hope that is the case.
Perhaps you’ve heard “you are what you eat,” but did you let that sink in? Did you really comprehend that you are just a recycled chicken, bean or apple?
Chemically speaking, you, me and the rest of life on planet Earth are mostly just water. Carbon-based compounds like sugars, proteins, lipids and nucleic acids make up most of the rest. Atomically speaking, life is mainly recombinations of the atoms Carbon (C), Hydrogen (H), Oxygen (O), and Nitrogen (N) or CHON. Indeed, a full 96% of anything “living” is made of these four atoms.
As we proceed through our lives, we consume or run out of our (CHON) building blocks. As placental mammals, we simply steal those components we need from our mothers’ blood supply, at least early on. Other species needing to develop get what they need in other ways, like from egg yolk sacs, but we are all still after the same CHON.
Life on Earth has just the four basic macromolecules that build it: carbohydrates, proteins, lipids and nucleic acids. These are all based in or made of the atoms CHON. Think of these atoms as the Legos that build life, with most of it being a simple combination of two Hs and one O (H2O).
So, we really are what we eat? Yes! Your DNA, hemoglobin, collagen, cholesterol and countless other macromolecules are not really yours. They are made of atoms taken from the organisms you or someone else killed. There, I said it, life is reliant upon death. You or someone else must kill something else, which wants to live, in order for your life to continue.
The atoms of CHON that we are converting, expelling and consuming on a daily basis are replenished by the species we consume, be they plant, fungi or animal. Argue all you want on the morals of life and death, but most species on Earth rely on death in order to live.
I often use the analogy of Lego pieces in class to explain reality. In short, life is made of the same very basic building blocks or Legos. One person may have built a huge Lego house and another a Lego helicopter. If you break them both up into individual Lego pieces, then you could also build a Lego car, boat and train.
Same basic parts but different things.
If one animal species does not steal the Legos of another, then it perishes. One must die in order for the other to live. The DNA code directs life and the behaviors of life, be they hunger or hiding.
Just a competition of selfish genes perhaps? No matter, you can rest assured that you really are what you eat — literally so.