Intro
UDCA makes a distinctive grey-black cloud at the bottom of a toilet bowl. It thus serves as a good dietary tracer, allowing correlation of intake with output.
UDCA has beneficial gut properties and at low dosages is benign.
Method
Look at your stool.
If you see the black cloud, stop taking UDCA.
If the black cloud is absent, start taking UDCA.
Dosage
Take 1x UDCA nightly
Conclusion
This won't give perfect precision regarding individual dietary errors. But it reduces ambiguity tremendously, permitting much better learning curve.