I could have given myself quite a bit of angst over abusing green tea (defined as drinking more than one cup every 72 hours) earlier this week...except I ran out. [To be dealt with in the weekly shopping trip.]
The practical concerns are the same as ever: it's one of those "conscience says all choices are sin" paradoxes. In this case, I will not be mastered by anything from I Corinthians.
After all: is it really a difference in violation, to choose to risk a tolerance to caffeine and theophylline, rather than the certainity that exhausting cerebral glycogen is going to stop attention to task dead in its tracks?