The great unwashed

[TimberWolf]

Biochemistry then. That's a good question for the congregation; how many average human turds would be required to keep a 100w light bulb running for one hour?

Use one of these to find the calorific content, but replace the bean shaped object with poo.

[TimberWolf]

The energy isn't coming from within the nucleous, it is being released from the chemical bonds between the atoms.
I don't believe there should be any mass lost as per the constant mass law of chemical reactions (although i'm not sure if that law includes the sort of miniscule amounts you refer to)

The loss of mass in chemical reactions is tiny (M=E/c^2). Even spinning an object increases its mass by an amount probably too small to be measured. The earth also gains mass from being heated by the Sun.

[Peoplesoft bloke]

Only if everyone breaths in at once.

Or even breathes.