Green te a is an increasingly popular weight loss supplement. A comprehensive review of the clinical evidence though has found that a person’s bank balance is probably the only thing that will get lighter by buying these supplements or consuming foods and drinks that have it added to them.
Green tea is a popular beverage with a long history of human consumption. Improvements in heart health, lower cancer risk and sharper mental function have all been linked to drinking green tea.
One of the more recent health claims made about green tea is its ability to help with weight loss so it is no surprise that food manufacturers have been quick to jump on this with a range of beverages and supplements now appearing with green tea extract in it.
Green tea is believed to be able to increase a person's energy output which could help with weight loss. Many of the commercial green tea weight loss preparations contain higher concentrations of ingredients (specifically catechins and caffeine) linked to weight loss than the typical green tea beverage prepared from a tea bag so it’s the supplements that are studied in clinical trials, rather than the beverage.
So does popping a green tea extract pill help someone lose weight? Many clinical trials have been carried out with different findings from each of them. Combining all of the research together has been the aim of the latest Cochrane Review  which is in the upper echelon of evidence-based recommendations.
The review looked at 15 weight loss studies of around 3 months duration each, and three studies measuring weight maintenance. Each study involved some form of green tea preparation given to one group of participants with the results compared to a group receiving a placebo. All studies involved the participants being blinded to which group they were allocated to.
The clear conclusion was that weight loss in people who had taken a green tea preparation was not statistically different to the placebo group. The absolute amount of weight loss seen was very small and is not likely to be clinically important. Studies examining the effect of green tea preparations on weight maintenance did not show any benefit either compared to the use of a placebo.
What it all means
If green tea is a true weight loss miracle, then most of the miracle will be because a person believes it works and adjusts their eating and activity habits accordingly.
Confused about the mixed soup of nutrition messages being stirred through the media? Tim maintains an active nutrition blog at www.thinkingnutrition.com.au  where you'll find the latest nutrition research and controversies discussed in straight forward language, distilling out what you need to know for your better health.