Starch as the predominant ingredient of human food is rapidly degraded in the gastrointestinal tract by salivary and pancreatic α-amylase to maltose which is further hydrolyzed by maltase localized in the brush border of the small intestine to glucose. Glucose is immediately absorbed leading to hyperglycemia and consequently to hyperinsulinemia. Both phenomena are undesirable in diabetics and in obese patients. The inhibition of the digestion of starch leads to a decrease and a retardation of glucose absorption. In nature, α-amylase inhibitors are found in wheat and other grains (Shainkin and Birk 1970). Several inhibitors of amylase and α-glucosidase have been developed (Bischoff 1991). Animal experiments with high doses of absorbable α-glucosidase inhibitors indicate that lysosomal storage of glycogen may occur (Lembcke et al. 1991).