Quick notes on the Glycemic Index:
Defining the glycemic Index- “The glycemic index, or glycaemic index, (GI) provides a measure of how quickly blood sugar levels (i.e., levels of glucose in the blood) rise after eating a particular type of food. The effects that different foods have on blood sugar levels vary considerably. The glycemic index estimates how much each gram of available carbohydrate (total carbohydrate minus fiber) in a food raises a person’s blood glucose level following consumption of the food, relative to consumption of pure glucose”
Issues to why rating foods on their GI is a non issue:
GI values are determined in an overnight-fasted state using isolated foods. This is not a reflection of real life, as most will be consuming other foods along side the carbohydrates that can drastically alter GI e.g. co-ingesting protein, carbohydrates, fats & fibre. Particularly fat slows gastric emptying and thus glucose into the blood, ultimately lowing the GI.
Secondly there is an overlap of previous meals/nutrients being absorbed & digested, further blunting the GI of a particular carbohydrate of a future meal.
Conclusion & Application:
Carbohydrate foods are better judged on the basis of degree processing, refinement, or alteration/removal of micro nutrition — NOT on the basis of GI.
For the majority of us, choosing foods based on their GI is a non issue for the reasons I have stated above.
The only exception to this would be an endurance athlete who would require isolation high glycemic carbohydrates during competition. E.g cyclists and long distance runners.
Also those who train more than once per day (likely endurance athletes) would benefit from consuming high glycemic carbohydrates in between sessions, where speed of glycogen re-synthesis is important. Whereas the majority of us who train once per day or training sessions are spaced more than 24 hrs apart such as resistance trainers, speed of glycogen replenishment is less of an importance. Another exception to this maybe is if you were to train late in the evening and then again first thing the following morning.
The final thing to consider is ultimately preference, I know some people who just like the taste of whey and dextrose post workout. If this is you, that’s fine. Just realise it is not necessary if you are resistance trainer, who trains once per day. As long as sufficient carbohydrates are consumed, that is the most important factor.