Have you ever wondered about when you lose weight what happens to the mass you lose?
I didn’t think of it either. My first thought was that you excrete it. You lose some water and salt to sweating, but I figured that got replaced so didn’t figure into long-term weight loss. I didn’t wonder how the mass you lose would get to your kidneys or bowels.
I read recently that it doesn’t. I read that the mass you lose when you burn fat exists your body in your exhalation. I confess I haven’t looked it up for a second opinion, but it made sense from a few perspectives.
We replace some oxygen in the air with inhale with carbon dioxide in the air we exhale, meaning our bodies add carbon to the air. I think we call that process respiration. It must help us store energy in chemical bonds that our bodies can later use to move, create heat, process chemicals, and other things. Carbon weighs something so we lose mass in the process. According to this model, you lose weight by exhaling more (and not eating more).
It would make sense that exercise would use that chemical energy and that our bodies would respond by replenishing it, which would cause us to breathe faster, losing mass. If our bodies store energy in muscles and fat that the carbon we exhale comes from there. I would guess the water and salt in sweat don’t come from structural parts of our cells but that carbon does. If we lose carbon, we probably decrease the weight of a cell.
I don’t know about you, but that sounds intriguing and cool to me. I wouldn’t have thought I lost weight by exhalation. I’m sure the explanation is missing important details, but if it’s reasonably accurate, I can see why losing weight would take so long. Breath doesn’t weigh much relative to your body, let alone the difference in weight between what you inhale and exhale, so you’d have to exhale a lot to lose much weight.
Also, it suggests that you can measure how much an exercise causes you to lose weight by how much extra breathing it causes. Running a marathon makes you breathe more, but not full-on pant, but it does so for four hours, so this model suggest it would cause you to lose weight. Lifting weights and running sprints cause you to breathe heavily, but briefly, so this model would suggest lifting sporadically might not lead to much loss, although it also suggests that lifting enough could lead to as much weight loss as cardiovascular training.
Burpees make me breathe so hard I can barely think for thirty seconds to a minute. I wouldn’t object to someone saying they made me pant like a dog (I enjoy playing with dogs, after all). All that heavy breathing, however brief, must add up over time.
The question remains if the exhaled carbon comes from muscle or fat. In my case, burpees have caused my muscles to grow, so they must have gotten extra carbon. Wherever the carbon comes from during exercise, in the long run it must come from fat if I eat the same.
As far as science goes, this is all just speculation, though it seems testable. I’ll have to look it up. As far as playing with ideas goes, I find this kind of thinking fun.
I like the idea that you can tell how much energy an exercise burns based on how much it makes you exhale.
Read my weekly newsletter
On initiative, leadership, the environment, and burpees