Last Friday, I wrote about some of the very basics of biochemistry. We are what we eat, but to let that fact really sink in means diving into the atomic make-up of life.
The macromolecules that make up life are just a recombination of the atoms, remember CHON, and a few others like phosphorus (P), sodium (Na), sulfur (S), and potassium (K). These are all floating in the molecules that comprises most of life, H2O.
Collagen is the most common protein in our bodies, and it’s used in a variety of ways, famously building our skeleton, tendons and ligaments. Collagen’s molecular formula is (C65H102N18O21), or more simply, just CHON.
The glucose that so many diabetics must monitor daily is C6H12O6 and the insulin protein that regulates glucose levels in your blood is just C257H383N65O77S6. I could go on but you get the idea, it is all just mostly CHON. To make all the molecules of life, you simply need the CHON building blocks, getting them is what gets interesting. A cheetah running after a gazelle at 70 mph is really just chasing CHON.
The atoms of life just get recycled. Mufasa covered this concept pretty well in the Lion King.
So if atoms are recycled, when we lose weight, just how does it get out of us and where does it go? The first time students hear that we just breathe the weight out, there are always a few stunned looks. Explaining that the pounds they lost just contributed to plant growth can get you a few more stunned looks. Most of that 10 pounds you dropped for that beach vacation left your body via your lungs as carbon dioxide (CO2). No magic, you just breathe it out.
The Krebs Cycle is named after Hans Krebs, who was a pioneer in the study of cell respiration. The goal of cell respiration is making the chemical energy of life adenosine triphosphate, ATP, or just C10H16N5O13P3. This ATP stuff is basically the gasoline of life.
During the process of making this ATP, some carbon atoms get removed from chemical intermediates in the Krebs Cycle. The lost carbon atoms get joined with oxygen, and you breathe it out as CO2.
You lose lots of carbon when you burn lots of ATP. ATP is heavily required for muscle contraction, so get moving. The more ATP you burn, the more carbon you lose from the Krebs Cycle, and carbon is the framework atom for building all macromolecules, especially fats. If you are losing more than you are taking in from your diet, then you lose weight, literally with every breath as you work out. That exhaled carbon will often end up being absorbed by some photosynthetic organism since they can get their carbon from the air while we must kill to get ours.
Ironically enough, if you grow your own vegetable garden, you are just consuming some of the carbon you breathed out while doing your gardening, technically cannibalizing your recycled self as you eat that corn — enjoy.