Be careful, Some processed foods that are considered low-medium on the GI index are almost as bad as high GI carbs because their high in calories. Some examples are wheat bread, whole grain pasta, and brown rice. A slice of miltons whole-wheat bread from costco has 120 calories. A cup of vegetables usually only has around 30 calories. Both have about 3 grams of fiber. So even if your not eating high GI carbs, you may not be eating the lowest GI's foods..
From my experience, a 40/30/30 diet using processed carbs like bread yielded better results than a high-carb diet using the same type of carbs. So, you will probably get results either way. I get better results keeping my carbs the lowest, preferably between 25-33%. Eating the lowest GI carbs, like fruits and vegetables, makes this approach more attainable.