This post is getting somewhat interesting...
The GI itself is relative to a few things. A carbohydrate food's GI is decreased once taken with other things. Adding a protein food to a high GI carbohydrate will do just this. And the more the meal gets mixed, the more the GI gets affected.
Bearing this in mind, we also must consider that glycogen synthesizing mechanisms are, on a per unit time basis, finite, and taking any more carbs per unit time than glycogen synthesizing mechanisms can handle is likely to lead to a carbohydrate spillover, with such excess glucose being stored as fat, all else being equal.
Furthermore, glycogen replenishment in weight lifters and bodybuilders depends on the situation. What sort of workout was performed? Was it one that significantly depleted glycogen stores i.e. high volume, high rep, burn/pump sets? Or was it a low volume, low-rep, max weight workout where less glycogen is likely to be used?
To add to this, one little study that I read in Muscle & Fitness several years ago reported that weight-lifting type activity often lead to microtrauma of the affected tissues (muscle....) and it was observed that such damaged tissue exhibited insulin resistance until all such DOMS disappeared.
Would it be wise then, to whack in the high GI carbs when there is a chance that you are in a state, albeit temporal, of greater insulin resistance? As an aside, this is something the "no pain no gain" types might want to bear in mind - DOMS is no indication of growth stimulation even though it is an indication that the muscles have become retarded to insulin.
One must consider the load on the pancreas when high GI foods are ingested. All else being equal, pancreatic shut-down does occur when the pancrease is overworked. Pancreatic tumours are not too far fetched too. Too much carbs too soon causes one's pancreas to work furiously, churning out tons of insulin in a panic-attempt to maintain glucose homeostasis. Do have pity on the pancreas. We need it to live.
That being said, is there a time and place for high GI carbs? Yes - pre-workout, taken with a fast protein. In this instance, we do not want gastric emptying being impeded by a slow-digesting lest this affects protein digestion which would then affect the state of hyperaminoacidaemia that we are hoping is induced by quick assimilation of the fast protein. Thus, a fast-digesting carbohydrate will be less of an impediment than a slow-digesting carbohydrate - the carbohydrate's GI then becomes a question of being a necessary evil since a fast digesting carbohydrate must have a high GI, and vice versa.
A fast-digesting carbohydrate will work better at keeping the liver busy too, and so more protein, in hyperaminoacideamic circumstances, would escape liver deamination to make it to your bloodstream, and from there, to your muscles.
Apart from such considerations, and taking into account the fact that bodybuilders tend to have mixed meals all the time or protein predominant meals, low GI, or lower GI as the case may be, seems to be the only way to go since it inevitably gets decreased unless we simply took a high GI carb on its own on an empty stomach.
Protein synthesis from the workout occurs over a period of 24-48 hours and so we spread our nutrition over such a time-frame, especially if post-workout insulin resistance could be present. It is thus opportune to have a slower digesting protein and carbohydrate meal post-workout for such trickle-feeding. This is the reason why Driver is a slower-digesting protein, and also the reason why a solid meal post-workout is also good medicine if you do not have access to a liquid meal that is slower digesting.
We simply must bear in mind the physiology of the situation and plan our meals accordingly.
Godspeed, and happy HSTing
