Oatmeal and oat flour are both made from whole oat groats and therefore have the same nutritional profile. The difference between the two comes from the milling or grinding. Oat flour is more finely ground and has a finer texture than oatmeal. While oatmeal and oat flour are both made from grinding oats, oat fiber is made by milling just the oat hull. As the name suggests, it is full of fiber. At 0 grams of net carbs, it is also low-carb and keto-friendly.