Drat, I know I read something on this the other day, but can't find it now.

Basically, 2-3 "hits" a day is fine, a "hit" is just under one cup of coffee, 1 cup tea, 1 50g choc bar, 1 can cola.

I tend to drink decaff and have maybe 5-40g choc a day: I know I like my chocolate more than my coffee! I also will be drinking more hot juices (made with concentrate) than decaff in the winter; I can't do hot juice in the summer!