Fiber is one of the most underrated nutrients out there—and it’s also one of the most essential for your gut microbiome. Our microbiomes evolved on wild, plant-rich diets with 100+ grams of fiber daily. Today, most of us get less than 15 grams per day.
But here’s what most people don’t know: there are different kinds of fiber, and each type plays a distinct role in supporting your gut health.
Let’s break it down:
1. Soluble Fiber Found in chia seeds, oats, beans, and apples, soluble fiber dissolves in water to form a gel-like substance. It slows digestion, helps stabilize blood sugar, and most importantly for your microbiome, it ferments in the gut to produce short-chain fatty acids like butyrate. These compounds reduce inflammation, strengthen the gut lining, and improve immune function.
2. Insoluble Fiber This is the roughage found in veggies, seeds, and whole grains. It doesn’t dissolve in water and doesn’t ferment easily. Instead, it adds bulk to your stool and keeps things moving. This type of fiber is critical for digestive motility and preventing constipation.
3. Resistant Starch This lesser-known type of fiber resists digestion in the small intestine and makes its way to the colon intact. There, it ferments and fuels beneficial bacteria lower in the gut—the region where microbial diversity is especially important. You’ll find resistant starch in green bananas, cold cooked potatoes, legumes, and grains like barley.
Why it matters: Each type of fiber feeds different kinds of microbes. And microbial diversity is key to a resilient, well-functioning gut.
Eating one type of fiber in isolation—say, just oats every morning—won’t cut it. What your gut really thrives on is variety. The more diverse your plant intake, the more diverse your microbial ecosystem.
Forget the fiber supplements. Build a gut-friendly plate instead. Mix and match fruits, vegetables, legumes, seeds, and whole grains. Your microbes will thank you.
Want a real-life example? Check out my Instagram video about the three main types of fiber and how to make my Prebiotic Power Balls! Don’t forget to give us a follow :)
