metabolism - When you lose weight, how does the mass exit your body?

As a thought experiment, consider the case of Angus Barbiery, who allegedly lost almost 200kg in about a year by not eating at all, save for necessary nutrients provided as supplements.

My question is, where did those 200 kilograms go.

And please, don't suggest that it was "converted to energy". 200 kilograms of mass would be approximately equivalent to 1.8*10¹⁶ joules. For comparison, Czech nuclear power-plant Temelín generates approximately 4.3*10¹⁶ joules of energy.

So how does the mass exit the body after the glucose is metabolized?

Answer

as CO2 and water

in respiration sugar (or fat) is combined with oxygen to produce energy(ATP and heat), water, and CO2.

fats are converted to Acetyl Co-A just like glucose is, the rest of the metabolic pathway is exactly the same.