Glucomannan is adietry fiber composed of mannose and glucose . Glucomannan has been used to support wight reduction because it promote satiety , delays gastric empyting time , and slows small-bowel transit time . Glucomannan's ability to delay gastric empyting time supports post prandial glucose and insulin levels. glucomannan also has prebiotic properties which support the growth & activity of beneficial gut flora these species support the digestion of nutrients .