Steel-cut oats derives its name from the process by which it is produced - large stainless steel blades chop the groats into two or three pieces, resulting in a texture chewier and coarser than other oats. The cut pieces of groats are not rolled. They retain their shape ,this causes steel-cut oats to have more surface area, which slows digestion. A larger surface area causes the stomach to work longer to break down steel-cut oats. The glycemic index, a measurement of the rise in blood sugar, is only 51 for steel-cut oats compared with 66 for instant oatmeal.