Dave asked me to comment on his posts. And they seem similar in idea to what Joey McGee brought up earlier, as well.
If we are looking at what sorts of mechanisms can account for immediate effects, it pretty much has to be neurologic - whether perception is altered (such as endorphin release) or whether nerve signals are sent (or interrupted) which modify what is going on in the muscle. Even hormonal responses take longer than described. And remember that very little of the orange juice is absorbed in the stomach - a little water is about it. Some glucose, if present, will be absorbed in the stomach, but that's because it's a mono-saccharide. Most sugars are in the form of disaccharides and have be to split into mono-sacchrarides by enzymes in the small intestine in order to be absorbed. And you need the right receptors. Same goes for other substances in the OJ, such as potassium. So anything which depends upon absorbing something from the OJ will take much, much longer to work than what was reported.
There is a limit to how much physiological change we want to see in response to smell, taste or expectation. After all, if we are wrong, we can be much worse off than we were before (even dead in the case of hypoglycemia). And if we are right, the best we can achieve is a beneficial effect a few seconds or minutes before it was going to happen anyway. So the evolutionary pressure for this would be slight.
We already have a lot of good knowledge about the body's responses to starvation and subsequent re-feeding. And this situation doesn't apply in Robert's case anyway. We do see some physiological responses to taste when it comes to preparing the GI tract for digestion. And those responses differ depending upon taste (fats vs. sugars, for example). We get immediate responses in the reward center for tasting something sweet (and interestingly we seem to be able to distinguish between artificial sweeteners and sugars).
You would have to explain how muscle cramps serves as a useful strategy to correct some deficiency, though. If anything, it will prevent activities which might correct the problem. The only real benefit is to stop someone from continuing to exercise when their muscles are ill-prepared.
Linda
