Special Microbes in the Gut Flora Improve Fiber Degradation in the Gut Mystery Solved? Previously little-noticed microbes in our gut could explain why some people are better "food converters" than others. An experiment reveals that certain archaea help the rest of the gut flora to break down fiber more efficiently and completely. As a result, the food provides the hosts of these microbes with more energy and calories. A hallmark of such "super-utilizers" in the gut is increas