Starch and sugar digestion continues until all the polysaccharides and disaccharides are broken down into monosaccharides. Since much of the carbohydrate in your diet comes from starch, and starch is made entirely from glucose, about 80 percent of the starches and sugars that you eat end up as glucose. The rest is broken down to fructose (about 15 percent) or galactose (about 5 percent).
