Peter Attia

So some soluble fibers are fermentable, but don't form gels.

Others are gel-forming, but poorly fermentable.

And some can do both, and some may do neither.

All of this is to say, this is a bit of a mess and sometimes can be a little hard to wrap your head around.

For the sake of my lack of brain damage and anybody else's listening, we have included a table in the show notes of common fibers along with all their properties and the food sources you can find them in.

So if at the end of this podcast, you're thinking to yourself, all right, I kind of want to beef up my intake of this fiber and this fiber, and I frankly care a lot less about this type of fiber.

We want to be able to help you do that in terms of understanding what sorts of foods you'd find that in, and of course, what supplements.

Yeah, so when you take fiber from a whole food source, which I think is what we mostly want to be able to do, you're typically going to get a mix of different fiber types, and therefore they're going to have different properties.

So cellulose and lignin, which are insoluble fiber, are structural components of plant cell walls.

So that means that any whole plant-based food you consume will have some amount of insoluble fiber.

But the exact quantity is going to vary across plants, though vegetables will typically contain more.

And within fruits, peels and skins would also contain more than the meat of the fruit, so to speak.

When it comes to soluble fibers, some foods are especially high in certain types.

So, for example, oats are packed with beta-glucan, which is a soluble gel-forming fiber that's also fermentable by the gut biome.

So when you eat oats, you're getting insoluble fiber from cellulose and then the beta-glucan, and you're getting both gel formation and the fermentation-driven prebiotic effects that make those short-chain fatty acids, which also have a positive and favorable effect on blood glucose.

Now, beans, on the other hand, don't contain any single dominant fiber.

They're high in fiber overall because they provide a diverse mix, including resistant starches, which I want to come back and talk about.

insoluble fiber, and soluble fibers with varying degrees of fermentability.

So when you get fiber from whole food sources, just remember you're getting a mixture of fiber types as opposed to just one.

Yeah, yeah.