## Weight lost as carbon dioxide?

Human Anatomy, Physiology, and Medicine. Anything human!

jonahsaltzman
Garter
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Joined: Sat Feb 04, 2012 3:06 am

### Weight lost as carbon dioxide?

I've been wondering, when weight is lost as a result of caloric restriction, is most of the mass lost as carbon or water? I did some not too scientific calculations below, and I think I got that you could only lose around half a gram per day of carbon dioxide:

According to wikipedia, the average breath is 0.5L
There is approximately 5% more CO2 in an exhalation than in an inhalation
So:
(0.5L)*(16 breaths/min)*(1440minutes/day)=11520L of breath per day
Atmospheric CO2 = ~0.04%
11520L*0.0004=4.608L CO2 inhaled per day
(4.608L*0.05)= 0.2304L net additional CO2 exhaled per day
According to wolframalpha, 0.2304L of CO2 = 0.424 grams CO2 lost per day (at STP)

And yet, I've lost around 5 pounds in almost three weeks, so where did the mass go? Was it lost as water? This weight loss was from caloric restriction, not exercise, so I imagine that my respiration did not increase significantly...

JackBean
Inland Taipan
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Joined: Mon Sep 14, 2009 7:12 pm
I don't think it's 5% of the original concentration, but 5% in general.
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

allenePanek
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Joined: Wed Feb 15, 2012 9:17 am
The primary reason we need to eat food is to provide fuel for the body. This fuel comes from the breakdown of carbohydrates, proteins, and fats.

JackBean
Inland Taipan
Posts: 5694
Joined: Mon Sep 14, 2009 7:12 pm
Really? Do not say so!
http://www.biolib.cz/en/main/

Cis or trans? That's what matters.

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