You can change an unrefined carbohydrate into an even slower releasing one by adding protein as you eat it.
So, if you’re having porridge you could add ground nuts and seeds (vegetable protein) and if you are having a jacket potato then you could add tuna (animal protein). You could also sprinkle cinnamon on your porridge along with the ground nuts and seeds. Cinnamon is helpful in balancing blood sugar, as it improves the transport of glucose into your cells.
According to PaneraBread.com, protein slows down the rate at which your stomach empties the food into the next part of the digestive tract and so it slows down the emptying of the carbohydrate too.