I am feeding the troll a bit... sorry guys and gals.
It is not just GI thats an issues it is also the glycogen load. Even Mark's fruit post recently made me think a little more on this when he talked about the high sugars in watermelon but left out that load was acutally low. I think both GI and GL are needed to make a proper judgement of blood sugar spikes. GI is how much a certain amount of carbs in a food will raise you blood sugar and GL is how much grams of carbs are in that particular food.
Now nature seems to have been pretty smart about this. Usually most fruits either have a high GI or a high GL but very seldomly do they have both. Watermelon has a high GI of 72 but a low GL of 4. That means that watermelon sugar has a strong effect on blood sugar but there is very little sugar per serving. Now look at apples, low GI of 39 but a slightly higher GL of 6. Then blueberries in the middle with a GI of 53 and a GL of 5. Overall fruit are pretty balanced and you would be hard pressed to find a high GI, high GL fruit. Now to compare.
Lets get the worst culprit out of the way, a bagel has a GI of 72 and a GL of 25 which must have a mind boggiling effect on blood sugar. Wholegrain pasta is at GI 37 and GL 8 which isn't so bad at first glance. Most whole grain breads are around GI 60 and GL 7.
So the whole grain stuff is not as bad as the white refined breads but still worst than the fruits (veggies are even better). But there are a couple other factors.
1. The grains don't provide nearly as much satiety thus you eat much more.
2. The grains usually are eaten in much larger servings thus you eat much more.
3. There is little nutrition even in whole grains compared to fruits and veggies.
It is sad that the measuring stick of our progress is the speed by which we distance ourselves from the natural world. Even sadder is that we will only see this when there is no nature left to save.