the technical physiology of fat loss

[dixiechick]

This is a query I have that has been at the back of my mind for a while.
I understand what fat loss is but have always wondered what happens in the body when you lose it. When the fat is utilised how does it get excreted? Is it through sweat or urine, or something else?
When people have a 'whoosh' do they get any physical symptoms that they can recognise?

[Phaedrus49er]

Fat isn't excreted so much as it's burned up as fuel. This is aromatically apparent if you or someone you know has done a true ketogenic diet--you can smell the ketones that are released from fat usage. You can't really flush or mobilize fat; it's just a fuel source that's stored away because it's more difficult to use than carbs or proteins.

Not really sure what a "whoosh" is

[LisaS]

CO2 and Water (and heat loss)
(without showing the real equations, essentially FAT + O2 = CO2 + H2O + heat + energy/ATP)
Much of which can go out in breath and the rest in urine, sweat, etc.