Does the glycemic index of a food increase when it has been blended? Because I blend many foods (including tuna), and I wanted to know if I was screwing myself by doing so. I was planning on trying those oatmeal shakes, when it came to my mind that a liquified oatmeal might be absorbed faster (like many foods with a high GI). If anyone would have info on this I would greatly appreciate it.
Yes. As example, fine ground white flour has much higher glycemic index than course ground whole wheat. As another example, the quick cook oatmeal has a higher glycemic value than old fashioned oats. I always buy the old fashioned oatmeal, not the quick oats. As a rule of thumb, the more processed a carb is, the higher the glycemic index. The reason for this is that the smaller or finer a carb is ground or processed, the quicker it is digested and absorbed and the quicker it will be in your blood and raise blood sugar and that is really the whole basis behind glycemic index. Whole, natural foods generally have a lower glycemic index than processed foods unless a lot of fat has been added as fat slows down digestion and will dilute or lower the glycemic index of foods but this is a double edged sword as fats and carbs are ultimately a bad combination and are really the essence of junk food. Mix your protein powder into your oatmeal, not your oatmeal into your blended shake unless it is immediately post WO.