Xylooligosaccharides, also known as xos oligosaccharide (CAS:87 99 0), are functional polymeric sugars formed by combining 2-7 xylose molecules with β-1,4 glycosidic bonds, and are an important member of the family of functional oligosaccharides. According to the definitions of the European Union and the European Food Safety Authority, xylooligosaccharides are dietary fibers in a broad sense. Thus, we can clearly see that one of xylooligosaccharide foods' benefits are its effect for weight loss.