From TFA, in case you were wondering:
> If you lose 10kg of fat, precisely 8.4kg comes out through your lungs and the remaining 1.6kg turns into water. In other words, nearly all the weight we lose is exhaled.
> If you lose 10kg of fat, precisely 8.4kg comes out through your lungs and the remaining 1.6kg turns into water. In other words, nearly all the weight we lose is exhaled.
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.