Peter Attia

Yeah, no, there are differences.

Not all fibers are created equal, and this is where, unfortunately, we do need to get into a little bit of semantics to be able to really make progress in this topic.

So there are lots of things that are classified as fiber, wide range of physical properties that a particular fiber might have, but these different properties produce different effects on the body.

So some fibers provide primarily microbiome support because they're actually fermented by gut microbiomes.

Some fibers can improve blood sugar, and we'll talk about how that happens, and others simply bulk up stool.

And again, the absence of those fibers would lead to altered bowel habits.

But importantly, not all fibers do the same things, and they don't all do them equally well.

So in the end, the function of fiber comes down to a bunch of properties of that specific fiber.

Okay, so the single most important one, and the one that I think most people will be familiar with, is what's called solubility.

Everybody's heard the term.

Let's just define it quickly.

Solubility means does something dissolve in water, yes or no?

So salt dissolves in water.

Glucose dissolves in water.

Fat does not dissolve in water.

So that's soluble, soluble, insoluble.

Similarly, we have soluble and insoluble fibers.

So let's talk about it.

Insoluble fibers obviously do not dissolve in water.

So think of an insoluble fiber as sort of roughage, something that remains largely intact as it moves through your digestive system.