Really? that's great! I'm trying to get people around me to do the same thing because you get about the same level of caffiene and all the extra herbal benefits.
I read this one guy, who did a study. In Chinese culture they use a tea to get grease off the fingers, you dip and it literally causes the grease to fall off your fingers. The guy thought that it might do the same for the fat on insides. The tea, however is rare and expensive, so he did some looking around and black tea and green tea share nearly the same compositions.
It also says that if you drink about 3 cups of tea before bed ( caffinated or de- ) it will help you further, why at night I don't really know, they didn't specify. But it seems to work well.
...Confession? I've taken to keeping kea packets in my pockets in case of 'emergencies' lol