Oolong or wu long tea is very popular in Asian countries like China and Japan. They believe it can help to keep them slim. Green tea, Oolong and pu-erh tea are known to help people lose their weight. Oolong tea is not well studied like green tea which is more popular. But there is scientific evidence that the tea can help to reduce weight.
Green tea, Oolong, and black tea all come from the same plant Camelia sinensis which contains antioxidant. The difference is in the time they are processed and fermented. The first one is processed the least so it maintains the green color. Black tea is processed the most and lose its green color. Oolong falls in the middle.
Wu long tea can increase your body metabolism and burn fat. People in Asia drink oolong with greasy food since they believe it is an effective fat blocker. A study by the University of Tokushima proves this. It the research 12 young Japanese adults were participated in a 17-day study. They found out that fat excretion on people who consumed oolong is twice higher than on people who were given placebo. In a 2001 Japanese study also found that drinking 1 litre of oolong tea daily can reduce your waist size and upper arms. They also found it can lower cholesterol levels.
Although Oolong is less popular than green tea, many so called experts claim that the tea is better than green tea because it can burn 2.5 times more calories. One study on 2003 by Komatsu from the Tokushima School of Medicine in Japan thinks that Oolong is better. But later study by Swen Wolfram in his paper Anti-obesity effects of green tea, suggested that Komatsu study may not be accurate due to wrong test method.
The fact is Oolong tea contains more polyphenols which makes it more efficient as a weight loss drink. Green tea on the other hand is better in fighting cancer than Oolong tea. So to lose weight you can drink Oolong and to fight cancer you can drink the other tea. A study also suggests that you will gain more benefit from metabolic boost from wu-long if you drink it just after a meal.
Oolong just like other herbs is safe to be consumed for a long time. If you are taking fat burner supplement for a long time, they can be toxic. I will not recommend consuming those supplements for a long time.