RS FibreBlend of resistant starches and other fibers RS Fiber contains two forms of type II resistant starch: green banana flour and powdered potato starch. Resistant starches (RA) are defined as starches resistant to human enzymatic digestion in the upper gastrointestinal tract; they are metabolized to short chain fatty acids by bacteria in the lower gastrointestinal tract; they therefore do not contribute to the increase in blood sugar levels. Common