Earlier quoted context omitted.
Not worth it. If you excercise hard for an hour daily you can triple your rate of breathing during that hour. So you get 26 instead of 24 hours of usual fat burning. Not much of a difference. Skipping some food can do much more.
I would venture to guess that it's not necessarily just that you are breathing in out out more often, but that the composition of the air you are breathing out changes.
> composition of the air you are breathing out changes.
Apparently experiments show it pretty much stays the same. To remove more CO2 from your blood your body just breaths faster. Maybe the process of exhaling can't achieve higher concentration.