A meta-analysis of green tea's impact on metabolism and weight-loss, undertaken by the Cochrane trust, finds no statistically significant correlation between drinking green tea and losing weight.
Other claimed benefits of green tea, such as longevity, have not yet been subject to scrutiny from Cochrane. Green tea still tastes nice, too.
As always, the On the Media Guide to Health News and Diet Fads is an excellent resource on this.
Just remember: when a study showing a weak or preliminary result that's pro-weight-loss is published, it is seized upon by companies that produce the product in question and its claims spun from "we think something small might be going on here" to "the pounds will melt away if you eat/drink/smear this stuff!" See also: "superfoods" "antioxidants" etc.
This review looked at 15 weight loss studies and three studies measuring weight maintenance where some form of a green tea preparation was given to one group and results compared to a group receiving a control. Neither group knew whether they were receiving the green tea preparation or the control. A total of 1945 participants completed the studies, ranging in length from 12 to 13 weeks. In summary, the loss in weight in adults who had taken a green tea preparation was statistically not significant, was very small and is not likely to be clinically important. Similar results were found in studies that used other ways to measure loss in weight (body mass index, waist circumference). Studies examining the effect of green tea preparations on weight maintenance did not show any benefit compared to the use of a control preparation.
Will Drinking Green Tea Boost Your Metabolism? Not So Fast
[Eliza Barclay/NPR]
Green tea for weight loss and weight maintenance in overweight or obese adults
[Cochrane]
(via Skepchick)
(Image: Panda Tea Green Tea, Lisa Amy, CC-BY)
