For anyone coming straight to the comments looking for an answer to the question: it turns into CO2 (and a bit of water) and you breathe it out.
When you realize that you have to breathe out all the weight you lose, I think it gives you a bigger appreciation for how difficult weight loss can be.
I've lost 16kg this year, which I attribute to 3 things:
1. being fairly strict with calorie intake - though I have gone over my limit a whole bunch of times
2. upping my running game - 80km+ most months
3. being diagnosed asthmatic (after 40 years of merely "you've got shitty lungs, sorry") and prescribed a morning+night inhaler
Dieting isn't new to me, I've been a fat bastard all my adult life. Previous attempts at losing weight have involved doing (1)+(2) and each time I lost weight and got faster. But with the diagnosis at the start of this year, and despite a higher calorie allowance, I've smashed my PBs at various distances - multiple times - and lost more weight (NB. because I started higher; I'm not at a record low, yet). So it seems pretty intuitive to me that "I'm better at breathing" has played a hell of a part.
I was under the impression (admittedly I don't know from where) that the process of burning fat actually dehydrates you and that you need to drink extra water if you want to facilitate it.
But here you remind me that the process of burning hydrocarbons nets some water, making me question myself. Of course metabolizing body fat is more complex than that, so this doesn't disprove it, but now I'm wondering if anyone else has more concrete information.
I sometimes ask the deep philosophical question, why does a tree not sink into the ground it grows out of? It blows people's minds when I explain that the reason is because the tree is mostly water and CO2, a gas and a liquid coming from the sky.
Thunderf00t had a great take on this showing why excercise is pretty much useless for weight loss.
You exhale same percentage of CO2 no matter how active you are so to burn more fat you have to make yourself breathe faster. You can do that with excercise which, if it's intense, can triple your rate of breathing. But if you do intensly excercise for an hour each day you just burn 26 hours of fat instead 24.
Not much of a difference. You can do much more with skipping some snacks or soda you ingest daily.
I once saw a documentary about "big animals" in the past.
Like, why did we have giant spiders and insects while they have a rather simple respiratory system that doesn't scale very well.
Because: trees!
Somehow plants managed to create wood, which bound the C from CO2, but the rest of the biosphere didn't know what to make of the wood. So there were more and more trees and more and more C got removed from the atmosphere. A much bigger part of the atmosphere was O2 and so the insects could grow bigger.
But in the end the fungi figured out how to make short work of wood and in turn released much of the C again into the atmosphere as CO2, so the animals shrunk again.
> Physical activity as a weight loss strategy is, therefore, easily foiled by relatively small quantities of excess food.
> Our calculations show that the lungs are the primary excretory organ for fat. Losing weight requires unlocking the carbon stored in fat cells, thus reinforcing that often heard refrain of “eat less, move more.”
"Eat less, move more." If anyone isn't aware of that by now, I don't know what to say.
the eating less part is more important (for weight loss) than the moving more part, especially because people doing exercise for weight loss often overestimate how many calories the exercise is burning, and underestimate how many calories are in food.
TFA does say "energy/heat + CO2 + H2O", but most of the output in terms of mass -- which is what one is interested in when it comes to losing weight -- is carbon dioxide.
It's pretty obvious when you do long fasts.
Every time I fast for more than I week, I lose several kilos doing nothing, not going to the bathroom even once except to pee.
Their point, which I agree is fairly unclear, is that the fat is not converted to energy, it's converted to CO₂ and water. That conversion releases energy, which you then use to move, but the total mass of the process is constant (conserved).
> Most people believed that fat is converted to energy or heat, which violates the law of conservation of mass. We suspect this misconception is caused by the “energy in/energy out” mantra...
I would not call it a misconception but simplification. Otherwise it is a very surprising article.
Observations from Figure 1, "Responses of a sample of doctors, dieticians, and personal trainers to the question “When somebody loses weight, where does it go?”"
Overstating the case about “0 dietitians ... only dietitians.” It looks as though about 2 people thought sweat was involved, and only 1 dietician answered co2. Pretty much everyone answered “heat.”
The question itself is shit, too, which is what happens when you dont have survey epidemiologists eyeball your questions. In “losing weight,” you’re doing a number of things - chucking the actual carbons (mass), and removing the potential energy stored as carbon-carbon bonds (heat). Given the widespread colloquialism of “losing weight,” people failing to interpret it as regarding the removal of carbons specifically isn’t unreasonable.
Sweat and urine are also correct answers, for that matter. Some of the carbon is used to create bicarbon and carbonic acids, via co2, which are lost in urine and sweat. Whether you want to count that as co2 or not is an argument about semantics - it goes through co2, but isn’t lost -as- co2. Of course, from the perspective of “it’s all breathed out as the result of perfect oxidation,” it’s wrong... but why let biology get in the way of undergraduate chemistry, right?
This isn’t a reflection on docs, PTs, or dietitians. This is GIGO.
At the risk of crossing the streams here... “wait! HN must be listening to the Microphone on my phone because I talked with my son about this exact topic 36 hours ago and now it’s in my HN feed!”
Yes, that’s a joke, but it’s also a completely factual statement (except for the Microphone thing) and a good reminder that with enough page views even extremely low probability events will happen with great frequency and predictability to someone in your audience (you just can’t predict to whom they will happen)
[+] [-] mikeash|8 years ago|reply
When you realize that you have to breathe out all the weight you lose, I think it gives you a bigger appreciation for how difficult weight loss can be.
[+] [-] darrenf|8 years ago|reply
1. being fairly strict with calorie intake - though I have gone over my limit a whole bunch of times
2. upping my running game - 80km+ most months
3. being diagnosed asthmatic (after 40 years of merely "you've got shitty lungs, sorry") and prescribed a morning+night inhaler
Dieting isn't new to me, I've been a fat bastard all my adult life. Previous attempts at losing weight have involved doing (1)+(2) and each time I lost weight and got faster. But with the diagnosis at the start of this year, and despite a higher calorie allowance, I've smashed my PBs at various distances - multiple times - and lost more weight (NB. because I started higher; I'm not at a record low, yet). So it seems pretty intuitive to me that "I'm better at breathing" has played a hell of a part.
[+] [-] _jal|8 years ago|reply
[+] [-] JoeAltmaier|8 years ago|reply
[+] [-] arikrak|8 years ago|reply
[+] [-] hammock|8 years ago|reply
a) the soil
b) water
c) the air
d) other
[+] [-] infogulch|8 years ago|reply
But here you remind me that the process of burning hydrocarbons nets some water, making me question myself. Of course metabolizing body fat is more complex than that, so this doesn't disprove it, but now I'm wondering if anyone else has more concrete information.
[+] [-] sillysaurus3|8 years ago|reply
https://hn.algolia.com/?query=by:dang%20%22work%20a%20little...
[+] [-] zappo2938|8 years ago|reply
[+] [-] ransom1538|8 years ago|reply
That is why you weigh less when you wake up in the morning (pre-bathroom -/+ yes some sweat).
[+] [-] maxerickson|8 years ago|reply
(if you figure ~2000 calories worth, it doesn't seem like the breathing weight out is so much the issue...)
[+] [-] scotty79|8 years ago|reply
You exhale same percentage of CO2 no matter how active you are so to burn more fat you have to make yourself breathe faster. You can do that with excercise which, if it's intense, can triple your rate of breathing. But if you do intensly excercise for an hour each day you just burn 26 hours of fat instead 24.
Not much of a difference. You can do much more with skipping some snacks or soda you ingest daily.
[+] [-] xisbad|8 years ago|reply
[+] [-] xhruso00|8 years ago|reply
[+] [-] thecity2|8 years ago|reply
[+] [-] adekok|8 years ago|reply
You can lose more than that, (see boxers before a weigh-in), but that's all water loss, and is temporary. And, with a strong likelihood of death.
[+] [-] fleitz|8 years ago|reply
[+] [-] JshWright|8 years ago|reply
Veritasium has a fun video demonstrating how unintuitive this is:
https://www.youtube.com/watch?v=2KZb2_vcNTg
[+] [-] StavrosK|8 years ago|reply
[+] [-] krallja|8 years ago|reply
(The answer to both questions is “mostly atmospheric CO2.”)
[+] [-] k__|8 years ago|reply
I once saw a documentary about "big animals" in the past.
Like, why did we have giant spiders and insects while they have a rather simple respiratory system that doesn't scale very well.
Because: trees!
Somehow plants managed to create wood, which bound the C from CO2, but the rest of the biosphere didn't know what to make of the wood. So there were more and more trees and more and more C got removed from the atmosphere. A much bigger part of the atmosphere was O2 and so the insects could grow bigger.
But in the end the fungi figured out how to make short work of wood and in turn released much of the C again into the atmosphere as CO2, so the animals shrunk again.
[+] [-] DoodleBuggy|8 years ago|reply
> Physical activity as a weight loss strategy is, therefore, easily foiled by relatively small quantities of excess food.
> Our calculations show that the lungs are the primary excretory organ for fat. Losing weight requires unlocking the carbon stored in fat cells, thus reinforcing that often heard refrain of “eat less, move more.”
"Eat less, move more." If anyone isn't aware of that by now, I don't know what to say.
[+] [-] DanBC|8 years ago|reply
[+] [-] Anderkent|8 years ago|reply
And that is more complicated than 'eat less, move more'.
[+] [-] pianom4n|8 years ago|reply
[+] [-] gebeeson|8 years ago|reply
[+] [-] s0rce|8 years ago|reply
[+] [-] Xophmeister|8 years ago|reply
[+] [-] zimbu668|8 years ago|reply
[+] [-] ZeWaren|8 years ago|reply
[+] [-] DoodleBuggy|8 years ago|reply
[+] [-] dugluak|8 years ago|reply
[+] [-] gnu8|8 years ago|reply
[+] [-] y4mi|8 years ago|reply
[+] [-] beefman|8 years ago|reply
[+] [-] somebee|8 years ago|reply
[+] [-] corpMaverick|8 years ago|reply
> We suspect this misconception is caused by the “energy in/energy out” mantra and the focus on energy production in university biochemistry courses.
I understand from the article that chemistry (Which I can't understand) tells you that it is converted on CO2.
But still. Clearly I can move because I have energy that I acquire from food. How is this wrong ?
[+] [-] wyufro|8 years ago|reply
[+] [-] sampo|8 years ago|reply
[+] [-] dandare|8 years ago|reply
I would not call it a misconception but simplification. Otherwise it is a very surprising article.
[+] [-] pwinnski|8 years ago|reply
0 doctors were willing to admit they didn't know.
0 dieticians thought sweat was involved.
Those results seem unsurprising.
Only dieticians correctly answered CO2.
[+] [-] arkades|8 years ago|reply
The question itself is shit, too, which is what happens when you dont have survey epidemiologists eyeball your questions. In “losing weight,” you’re doing a number of things - chucking the actual carbons (mass), and removing the potential energy stored as carbon-carbon bonds (heat). Given the widespread colloquialism of “losing weight,” people failing to interpret it as regarding the removal of carbons specifically isn’t unreasonable.
Sweat and urine are also correct answers, for that matter. Some of the carbon is used to create bicarbon and carbonic acids, via co2, which are lost in urine and sweat. Whether you want to count that as co2 or not is an argument about semantics - it goes through co2, but isn’t lost -as- co2. Of course, from the perspective of “it’s all breathed out as the result of perfect oxidation,” it’s wrong... but why let biology get in the way of undergraduate chemistry, right?
This isn’t a reflection on docs, PTs, or dietitians. This is GIGO.
[+] [-] eeZah7Ux|8 years ago|reply
From doctors, this should not happen.
[+] [-] agumonkey|8 years ago|reply
not sure it's this one https://www.youtube.com/watch?v=vuIlsN32WaE but close
[+] [-] perilunar|8 years ago|reply
[+] [-] unknown|8 years ago|reply
[deleted]
[+] [-] stillbourne|8 years ago|reply
[+] [-] yodon|8 years ago|reply
Yes, that’s a joke, but it’s also a completely factual statement (except for the Microphone thing) and a good reminder that with enough page views even extremely low probability events will happen with great frequency and predictability to someone in your audience (you just can’t predict to whom they will happen)
[+] [-] scottmcdot|8 years ago|reply
[+] [-] s0rce|8 years ago|reply