Myths and Truths About Fiber
February 18, 2012 §
The addition of insoluble and soluble fibers to processed foods may actually cause these foods to be even less nutritious than if they were not enriched with any fiber at all.
This hypothesis brings up another side to the fiber debate: the effect of dietary fiber on beneficial gut bacteria, as well as the bacterial fermentation of undigested soluble fiber into short-chain fatty acids such as butyrate. When we eat the soluble fibers found in whole plant foods, the bacteria in our gut ferment these fibers into short-chain fatty acids like butyrate, proprionate, and acetate, and greater amounts of fiber consumed will lead to greater short-chain fatty acid production. (14) In this case, naturally occurring soluble fibers are very important for feeding the friendly bacteria that live in our guts.
via Myths and Truths About Fiber.