When you lose weight, where does it go? This question and its answer are much more profound than you think. I recently ran across a YouTube video that argues for us to think differently about weight loss. The video is called “The Mathematics of Weight Loss,” presented by Ruben Meerman, a physicist from Australia. His theory on weight loss helps explain the obesity epidemic.
For example, why are millions of dollars spent in the United States on weight loss gimmicks? Because we really don’t understand where the weight goes when we lose it. If we did, we would be able to identify those gimmicks for what they are and save our money.
The heart of Meerman’s argument flows from an undeniable fact of the universe – matter doesn’t just disappear. When fire burns a log, the log doesn’t disappear. Instead, the log is turned into something different—but every atom of matter that was in the original log is present and accounted for in the leftovers after the fire.
Food science positions metabolism (and therefore weight loss) in terms of the energy released when your body uses food for fuel. That’s what a calorie is. It’s a unit of energy that is released from food. But this idea under-recognizes the fact that after the energy is released from food or fat, the atoms and their weight are still in your body. The leftovers have to get out of you before the weight is lost. So where do the left over carbon atoms go from a spent molecule of fat after your body has released the energy? The answer is: They go out in your breath as carbon dioxide.
Every breath that you exhale releases carbon dioxide from your body. Even though carbon dioxide is a gas at room temperature, that does not mean that it has no weight. It’s just that carbon dioxide gas has very little density, so you must exhale lots of it in order for it to weigh very much.
If we make a few reasonable assumptions, we can calculate how much weight of carbon dioxide our body expels in a usual day. I’ll use myself for this calculation because my weight makes the math easy. I weigh 220 pounds, which turns out to be 100 kilograms (100kg). The average volume of a resting person’s breath is 7ml/kg, which makes my average resting exhaled breath 700ml.
To provide some perspective, a can of coke is about 355ml. So each time I breathe out while resting, I breathe out about 2 coke-cans full of air. About 4% of that exhaled air is carbon dioxide. I’ll ask you to trust me with the intervening math and tell you that accordingly, each exhaled resting breath contains 51 milligrams of carbon dioxide.
Knowing that, we can make all kinds of interesting generalizations. For instance, a man my size doing only usual daily activity and not exerting himself can expect to breathe out about 2.2 pounds of carbon dioxide per day. That is all carbon dioxide that was released when my body used food or fat for energy.
As Meerman demonstrates in his video, that is potentially 2.6 pounds of fat that I lost! The reason that we don’t just lose weight sitting around and breathing is because of the food we take in every day. If I ate the equivalent of 2.6 pounds of fat today and I didn’t increase my breathing with exercise, I could expect to maintain my current weight. Instead, if I ate the equivalent of 2.6 pounds of fat but exercised rather intensely for one hour (1 hour with respiratory rate of 24 breaths per minute at 2 liters per breath) I could expect to lose a little less than ½ a pound (0.44 pounds actually).
What if I exercised that same hour, but chose instead to only eat the equivalent of 1.95 pounds of fat? Then I could expect to lose 1 whole pound that day. The unavoidable point is, if I’m not eating less and moving more (therefore breathing more), I’m not losing weight!
Now apply that to weight loss gimmicks such as “fat-burner” pills. If there existed a pill that caused your body to burn its fat, what would be the unavoidable consequence? The burning of the fat would release energy and carbon dioxide. It is not possible for the weight to leave your body without that happening. If the energy is not released to fuel the movement of your muscles, it still has to be expressed somehow. A safe assumption is that it might be expressed as heat, therefore increasing your core temperature, potentially causing fever. Plus, all the carbon dioxide would have to exit your body as extra breaths.
I’m reminded of a so-called fat-burner advertised with a Facebook ad showing a bowl of fat, and the fat magically disappears from the bowl when the product is sprinkled into the bowl. If the world actually worked that way, there would be no obesity epidemic.
So what final wisdom can I take from this analysis? First of all, recognize gimmicks for what they are. Simply put, if a fat-burner pill doesn’t give you fever and make you pant like a dog, it’s not burning any of your fat! The tried and true method of weight-loss is unavoidable; eat less and move more in order to lose weight.
If you chose to drink a Coke (and yes, I do like Coke just like everyone else) understand that every carbon atom in that Coke must leave your body in the form of carbon dioxide. Or else, it will be stored in your body as fat. I strongly recommend you watch Ruben Meerman’s video demonstration. It’s very entertaining and will help reset your frame of mind regarding weight loss. ν