Ok, I am posting the links to some blog entries by economist and fitness enthusiast Art DeVany, an advocate of what he calls "evolutionary fitness," which, while it may have merit, is not something I am really interested in because it is very anti-endurance sports and much more ideologically driven to results rather than enjoyment of the process, which is most of the reason why I cycle.
However, he makes some seemingly good points about the unadvisability of glycogen replenishment and carb loading, siting several academic papers and the marketing motive of a lot of the sports drink companies. The basic point is this: while sports drinks and carbs do improve performance during the workout, they blunt the hormone-driven training adaptation, so one would benefit from avoiding them during training.
Here are the links to the relevant posts. Some of the included sections of the academic papers are complicated, and the conclusions that Art draws and comments on do not necessarily follow from the papers, but he may be making a good point that millions of dollars of marketing may not want you to draw. However, since I am not familiar with the academic literature, I do not know if there are other studies that support or contradict these conclusions, or if his conclusion is the right one. So if some of you look at this stuff, perhaps we can collectively make more sense of it. I know it is a lot to read, but the top three are the most relevant. Thanks for your comments.