They eat certain carbohydrates (such as fiber) [0] that we consume and aren't able to digest by ourselves. This is why it's recommended to eat fiber [1], which

They eat certain carbohydrates (such as fiber) [0] that we consume and aren't able to digest by ourselves. This is why it's recommended to eat fiber [1], which many people do not eat enough of. [2] [0] https://en.wikipedia.org/wiki/Gut_flora#Metabolism https://en.wikipedia.org/wiki/Gut_flora#Metabolism [1] https://www.sciencedaily.com/releases/2016/11/161117134626.htm https://www.sciencedaily.com/releases/2016/11/161117134626.h... [2] https://www.webmd.com/diet/guide/fiber-how-much-do-you-need#1 https://www.webmd.com/diet/guide/fiber-how-much-do-you-need#...