first of all, congrats on noticing that your oatmeal only lasts a couple hours! I've seen some research say glycemic index for SC oats is 42 while rolled oats is 55 and instant is 83. I've seen other research say SC is 52/53 and rolled/instant are 57/59+

Remember glycemic load is also a factor. this is about the quantity of the food. According to data published in the American Journal of Clinical Nutrition, rolled oats have a glycemic load of 9 (low), while instant oats have a GL of 24 (high).

Building your bowl of oatmeal as outlined in the article will help with all of these factors AND your blood sugar and energy. Keep going, David! You got this!