Comment by wdporter
3 hours ago
My theory is that the only reason we need indigestible carbohydrate is to push out the indigestible carbohydrate that is already stuck in the colon. Therefore we need it either all the time or not at all. Does this make sense?
I see the logic there, and it's my understanding that the ancient Egyptian physicians believed something similar. Eating high bulk foods helped to prevent other food from rotting inside your gut.
Indigestible carbohydrate is a much broader category than fiber: -Soluble fiber -Insoluble fiber -Sugar alcohols like sorbitol -Resistant starch (though I'm unsure what the practical difference is between this and soluble fiber)
Insoluble fiber adds bulk to your stool, which I don't think there's a lot of evidence this is healthy. It's probably the main culprit in fiber-induced constipation.
Soluble fiber and resistant starches are probably fine if you're not overdoing it, and if you're on a low-meat diet it's probably how you get short chain fatty acids. It's worth noting that if you're not used to eating these molecules you won't have the bacteria so it'll take some weeks of gas before your system adapts.
Sugar alcohols of the right sort will certainly help your body clear out your gut. Xylitol is interesting for its dental health properties.
To your point: in much of the plant food we grow, there's a matrix of these carbs and digestible carbs. Eating a plum is probably fine. Eating purified sugar, even from plums, is generally bad for you. Eating purified sorbitol from plums won't make you feel good. Why should it be any different eating a bunch of fiber in the form of supplements? The human body is adapted/tuned to digest these molecules in the context of others.