Fiber feeds the good bacteria, it does not deplete it. The flora ferment the fibers, which are composed of long chain Sugar molecules. As the fibers are fermented the chains are broken producing smaller Sugar molecules that the beneficial flora feed on. In the process beneficial acids, such as lactic acid, acetic acid and fatty acids. These acids help to control fungal Candida and other pathogens as well as aids in the absorption of nutrients such as calcium.