Congratulations on taking charge of your health. Adult onset diabetes can be helped with eating foods that are appropriate for you. The glycemic index has some merits but not as much as discovering what foods you are allergic to and eliminating them.
Willliam Philpott, MD, did blood glucose testes on patients who had food allergies and fount that when some people ate a food they were allergic to, which had almost no carbohydrate in it such as cheese, they developed high blood sugar levels as part of an allergic reaction. I've heard people say their glucose levels go sky high if they eat too many nuts.
Get a test that does IgG allergens. The highest and most certain allergens come from dairy and wheat. If you crave any food you are more than likely allergic to it.
If you eat low GI but are allergic to the food then your insulin levels will not be balanced.
Exercise has been scientifically proven to reverse insulin resistance and metabolic syndrome. It's fun, it feels good and you'll live longer by exercising every day.