Yeah Its because caffiene interferes with the action of insulin which means glucose doesn't enter the cells and is left to circulate and is then stored as fat, it also increases adrenalin levels which encourages glucose levels to rise. A couple of cups a day is fine but drinking lots can have a negative affect! But if you like green tea that is very good for weightloss. x
Oooh, do you want a debate about that one?
There is some research to show that a
massive amount of coffee taken just before a high carb meal can raise insulin. There's also research to say that it doesn't. There's research to say this only happens with decaffeinated coffee (so probably not the caffeine at all). And there's research to say the opposite.
But, there's lots of research that suggests that caffeine increases fat mobilization, so if there was a negative impact with the insulin, it's likely to be outweighed by the fat metabolism benefit.
And of course, caffeine increases NEAT which can raise metabolism.
This is probably why so many body builders use caffeine pills to increase weight loss when they are 'leaning up'.
There's also a lot of research suggesting that caffeine has all sorts of other health benefits.
As for weight loss benefits of green tea, I think it's something like 10 cups a day for 2lbs weight loss in 6 months, but it's unknown whether other stuff could have happened to cause this as the research was very iffy. Whether this fantabulous extra weight loss would be the same on a VLCD isn't known.
Green tea like coffee also has health benefits too