Pay for Shit

It is well known that taking a shit or peeing is the third most enjoyable of the necessary bodily functions that we can control.

Imagine a world in which food was free. You could eat and drink anything without cost, shop for free, eat out for free and food was distributed free of charge. In this world, starvation would no longer exist.

Everything would be free for everybody until the age of 18. At this time, people would have sensors attached to their bodies that would monitor whenever they excreted; that is, peed or pooed. This would be connected to a wireless credit system that would charge everybody for "shitting" instead of eating.

How would this affect the world? Would it make it a better or worse place? Cleaner or dirtier? Perhaps starvation and obesity related deaths would become a thing of the past.