I think you are right about the good/bad point. Good reactions and bad reactions seem to make me smell. The worst part is, I can't be sure what is good or bad. Probiotics make me smell, for example. So do Antibiotics . Die-off makes me smell (which I presume is good). But garlic makes me smell (which I associate with a possible sulfur-eating bacteria issue. Garlic is also a big user of the FMO3 enzyme, I think). The question is, are they good or bad reactions ? I think its a bit like cleaning out a pool of clear water with mud at the bottom. Once you try to clear it up, the water becomes muddy. I couldn't say this is a universal rule though. At the moment I don't think it is.
Hopefully this is one of the riddles we will solve over time.