The study tested three groups of healthy vounteers who drank either oolong tea, pure caffeine, or a placebo for two weeks.
Compared to the control group, participants who drank oolong tea or caffeine increased their breakdown of fat by 20 percent.
But it was only oolong that kept going after participants fell asleep. This is linked to its affect on sleep.
Despite caffeine being noted for keeping people awake, researchers found there was no difference in sleeping patterns between the control group and the oolong drinkers.
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