The most common misconception among personal trainers is that the missing mass gets converted into energy or heat, while instead, most of the mass gets breathed out as carbon dioxide.
In a paper published in the British Medical Journal, the authors show that losing 10 kilograms of fat requires 29 kilograms of oxygen to be inhaled and that this metabolic process produces 28 kilograms of carbon dioxide and 11 kilograms of water.
If you follow the atoms in 10 kilograms of fat as they are 'lost', 8.4 of those kilograms are exhaled as carbon dioxide through the lungs. The remaining 1.6 kilograms becomes water, which may be excreted in urine, faeces, sweat, breath, tears and other bodily fluids, the authors report.
Now, before you start breathing your life out and get into hyperventilation, know that breathing more or faster, won't help you lose fat.
Quite in fact the answer will always remain the same: diet & exercising will always be king.