Fermented foods, on the other hand, are created through fermentation (duh), in which components of foods, like the natural sugars, are broken down by yeast and bacteria and result in food chock-full of probiotics (aka, the good bugs). Some examples include kombucha, kimchi, sauerkraut, miso, and yogurt, plus others.
To boil it all down to a one-sentence comparison: Fiber foods feed the good bugs in your gut, while fermented foods help increase the actual number of those good bugs. Both are ultimately important for optimal gut health, and one is not necessarily “better” than the other. However, if you’re just embarking on your gut health journey, you might want to get your fill of fermented foods before loading up on fiber.
On the mindbodygreen podcast, Pedre references a study1 in which researchers measured microbial diversity in folks who ate five to eight servings of fiber per day versus those who ate six cups of fermented foods per day: “What [they found] is that a high-fermented-foods diet increased microbial diversity in that group and lowered 19 inflammatory markers,” he explains.
The fiber-rich group did see positive effects on microbial function and immune response, mind you, but the fermented foods had a significant effect on inflammation. That said, you might want to up your intake of fermented foods before introducing a significant amount of fiber so you can reduce inflammation and increase microbial diversity before actually feeding those healthy gut bugs.
Again, just remember that both food groups are ultimately important for overall gut health. “I hate that they pitted fiber-rich [foods] against high-fermented [foods]. I think there should have been a third group where there was no diet intervention so we could see these two against that as well,” says Pedre. “But it starts to drop some really great questions here because I don’t think it’s about fiber versus fermented. It’s really about the combination of the two.”
