But each expired breath is saturated with water vapor. Does the 8.4 Kg out of the lungs include that water vapor, or is the expired water vapor a large proporti

But each expired breath is saturated with water vapor. Does the 8.4 Kg out of the lungs include that water vapor, or is the expired water vapor a large proportion of the 1.6 kg of water produced? It's probably more accurate overall to say that all our weight-loss gets expired into the atmosphere as gases, with the exception of some minerals which get excreted in feces and urine.