Let me begin by saying that I am anti-carb. I have a real thing against refined sugar. (But I do think artificial sugars can be much worse.) But I'd like to refine what you've quoted with a little bit pf personal experience.
My son is a Type 1 diabetic. His life depends on us calculating his carbs, calculating his insulin bolus to counter those carbs, and timing his insulin with his carb digestion as much as possible. From what we've seen, the glycemic index is a load of crap.
If my son drinks 45 grams of carbohydrates in the form of a soda is blood sugar will go up within 10-15 minutes. He will need 3 units of insulin to counter that rise. If he eats 45 grams of carbs in the form of a 50% white rice/25% brown rice/25% wild rice mix, his blood sugar will not go up for about 20-30 minutes. But when it does, it spikes up just as fast as the soda did, it only took longer to get the spike. He will still need 3 units of insulin. The only difference *that his body sees* between a Coke and the rice mix is the timing. From what I've seen, the rise isn't *gradual* in either case.
Let me put it this way: He has NEVER eaten anything and had his insulin requirements remain higher than his baseline (with no food) for more than 3 hours with ANY food.
What does slow down food sugars entering the body? FAT. Eating fat *with* carbs will slow down the carbs, sometimes dramatically.
But here's the real head-tilter: If he eats carbs with no fat, he gets 1 unit of insulin with 15g of carbs. Pretty straight-forward. If he eats fat with carbs, he'll need *more* insulin over a longer period of time. (It actually looks like we're giving insulin for the fat.) But if he eats nothing *but* fat, he won't need any insulin. It's like the fat doesn't just slow down the carbs, it actually magnifies it.
So my suggestion is this: Forget the glycemic index thing. Eat *natural* carbs (that your body actually recognizes) and eat a small amount at each sitting. I don't see anything wrong with eating 25g five times a day.
Don't stay away from sugar because it packs too much of a sugar punch. Stay away from it because it's been pulverized to the point where it's not even really *food* any more, it does you absolutely no good, and because we were not designed to eat a ton of it anyway.
This is not coming from a scientist or a doctor. This is coming from a woman who has administered or supervised almost 10,000 blood glucose readings, made a decision as to insulin dosage, and still has a living kid. (I must be calculating something right!)
Glycemic index as we know it (South Beach Diet etc.) attempts to summarize a curve shape in a single number. As such it cannot meet everybody's needs. In time, better measures will appear.