Although porridge oats are classed as a complex carbohydrate, they are easily digestible and many people find that they raise BG levels substantially. It's why they were often given to sick people. As with flours, the tendency is for producers to create products which users find quick and simple to use when making a meal. Proper groats, or steel cut oats. take time to took. Most people want to do no more than a few mins in a microwave. If you want to eat them, you really need to eat groats or steel cut oats, not rolled oats and certainly not quick cook oats. Here is a useful explanation of the different terms
oatmeal, steel cut oats, rolled oats etc.
Have a try at
Scottish porridge oats, not to be confused with the brand Scott's porridge oats which is more a marketing description. All sorts of tricks are used with misleading titles such as Original Oats, Traditional Oats. You're probably better off buying at a good health food shop or online. The pic below is of pinhead oatmeal, basically chopped groats. It takes time to cook and takes time to digest: