These biological changes lead to that ever elusive but always important goal: losing weight or more specifically burning fat. The secret with tea is that it contains polyphenols which are more commonly known as flavanols or catechins.
It's these compounds which are not unique to tea but are highly concentrated in it that are responsible for the fat burning. Two recent studies prove this point rather well. One study gave users an optimal amount of green tea for 12 weeks.
At the end of the study, the subjects total fat area, waist circumference, skinfold thickness and subcutaneous fat area were significantly reduced. In the other study the combination of caffeine and polyphenols was shown to significantly raise the resting metabolic rate of its subjects.
Basically, your body burns more calories even when you are not exercising.