>>...consume more fiber to increase the bulk...

Agreed that we all under-consume fiber, but I have to wonder if the stool type / frequency is directly causal or an indicator.

For example, HDL is an indicator but doesn't seem causal. Higher levels are associated with lower risk of CVD, but manipulating HDL (e.g. with niacin/B3) doesn't seem to confer the same benefits. There *do* seem to be some benefits (mostly skin health) associated with that 'niacin flush' - but it also raises systemic histamine levels. I also see it's been used for treating 'hardening of the arteries'; no idea if that's still valid.