We’ve recently received multiple questions about wu-long tea in regards to advertised slimming properties, so I’ve decided to shed some light onto the subject.
(People are often confused by the terminology used in advertisements for “wu-long slimming teas”. These advertisements seem to always use the more exotic sounding word wu-long, but both terms, oolong (generally used in English) and wu-long (generally used in Chinese), refer to the same kind of semi-oxidized tea. I’ll use the commonly used term oolong throughout this article.
Please visit our oolong information page for more general information on oolong tea.)
The story behind reported (advertised) weight losses based on the consumption of oolong tea
It seems that clever marketers have found a way to cash in on findings from recent scientific research on the fat-burning and anti-obesity properties of oolong tea.
In China, oolong tea has been reputed to help regulate body weight and increase metabolism for centuries. In recent years, a number of studies have been conducted on humans and laboratory animals to investigate the validity of this belief.
The recent surge of interest was probably caused by the latest publication on the topic by a group from the Nanjing Institute for Pediatrics led by Guo Xirong who conducted a 5-year study on childhood obesity. Amongst other findings that help to understand and control the development of obesity in children, the group confirmed that “the continuous intake of oolong tea contributes to enhancing the function of fat metabolism and to controlling obesity” (the press release titled Oolong tea helps you lose weight can be found here).
This recent study was preceded by a number of earlier studies with similar results.
W. Rumpler et al. from the Beltsville Human Nutrition Research Center, USA together with colleagues from the Department of Nutrition, University of Tokushima, Japan have published a study titled Oolong tea increases metabolic rate and fat oxidation in men in 2001 that investigated the effects of oolong tea consumption on energy expenditure (EE) of humans. The study focused on men between 25 and 60 years of age and the results show that while the consumption of oolong tea lead to an increase in EE of merely 3-4%, fat oxidation was increased by 12% in the group that consumed oolong tea (click here for the full text of the study).
A Japanese study titled Anti-obesity action of oolong tea presented the results of an investigation on the effects of oolong tea in a high-fat diet. The study was conducted on obese mice and the scientists found that while the consumption of oolong tea didn’t lower the mice’s appetite (i.e. food consumption stayed constant), it prevented obesity and fatty liver that was observed in the control group where oolong tea was replaced by water (for the full text of the study, follow this link).
Why oolong tea?
Results of the cited studies indicate that the observed effects of oolong tea consumption on fat oxidation and EE can be attributed largely to caffeine intake. But the studies observed greater effects resulting from tea consumption than from caffeine alone, so a synergistic effect of caffeine and the catechins contained in tea seems plausible.
An explanation for this could be the reported effect of tea polyphenols (i.e. catechins) on controlling the deposition of triglyceride (a chemical formed in our liver by the synthesis of sugar and fat and – if present in excess – ultimately deposited in fat cells). Polyphenols are reputed to activate certain enzymes that dissolve triglycerides and could therefore play an important part in controlling fat deposition. Since oolong tea contains high levels of polyphenols, it could be this effect that was observed in the cited studies.
Miracle or hoax?
A bit of both, really. As we’ve seen above, there is fairly conclusive scientific evidence that oolong tea DOES help controlling body fat.
However, the miraculous effects advertised by some dubious online vendors are just what they seem: too good to be true!
Oolong tea DOES NOT make you lose 30kg in 30 days (if you’re not changing the rest of your diet), but it is a great (and I haven’t mentioned yet – delicious!) way to help you control weight in conjunction with physical exercise and a healthy diet.
I want to conclude this article with a quote from W. Rumpler et al., which sums up quite nicely my feelings about this subject:
It is clear that consumption of oolong tea stimulates both EE and fat oxidation in normal weight men. This raises the possibility that tea consumption could have some beneficial effect on an individual’s ability to maintain a lower body fat content. However, any beneficial effect would only be realized if the effect was sustained upon chronic consumption of tea and the individual did not compensate with greater food intake in response to tea consumption.
We are offering currently about 15 different oolong teas from China and Taiwan (Formosa). Amongst them, we carry the famous Wuyi Rock Tea (Wu Yi Yan Cha) and many varieties of Taiwanese high mountain oolong (gao shan).
Please see our current pricelist for an overview of our extensive range of oolong teas.
[techtags: oolong, wu-long, wulong, tea, weight loss, slimming tea, polyphenols, obesity, burning fat]