I remember being young and hearing my grandparents talk about fiber. With my optimally functioning body, it seemed there were much more interesting (and less embarrassing) things to discuss.
In my mind, those were problems for people much, much older than me (like in their 80s)
They say every judgement you have will come back to bite you.
And now here I am at 50, not just talking about fiber but making a living doing it. And why stop at fiber? I spend my days talking to people about their poop in great detail.
Life is strange. But back to fiber.
Metamucil may be all our grandparents knew (unless they were well versed in herb and food as medicine). It is mainly psyllium husk, but it has a bunch of other crap you don't need, like yellow 6 and artificial flavor. There are much better options out there.
Fiber is useful for constipation, diarrhea, and overall gut health. I'd argue it's more important (and cheaper) than probiotics in many ways.
First it's helpful to understand different types of fiber and their uses: Soluable, Insoluble, Prebiotic and Resistant Starch Fiber.
Soluble fiber dissolves in water and forms a gel to line your digestive tract. It's best for treating diarrhea. Psyllium husks are mostly soluble. Oats too.
Insoluble fiber does not dissolve in liquid. It's good roughage to help keep things moving through your digestive tract if you tend towards constipation. Ground flax, quinoa, broccoli are a few examples.
Prebiotic Fiber contains non-digestible plant fibers that feed your microbiome, helping to keep you regular. Common ingredients include Inulin (from Jerusalem Artichokes), Pectin and Partially Hydrolyzed Guar Gum.
Resistant Starch is a specific prebiotic fiber that “resists” breaking down until it reaches your colon, where it helps feed your microbiome. It provides fuel for colon cells, buffers against leaky gut and can help lower intestinal inflammation. Green plantains, plus certain legumes and starches that have been cooled down and reheat: rice, potatoes, lentils.