Different outcomes of the effect of green tea on weight loss (WL) and weight maintenance (WM) have been reported in studies with subjects differing in ethnicity and habitual caffeine intake. Purpose. To elucidate by meta-analysis whether green tea indeed has a function in body weight regulation.Methods. English-language studies about WL and WM after green tea supplementation were identified through PubMed and based on the references from retrieved articles. Out of the 49 studies initially identified, a total of 11 articles fitted the inclusion criteria and provided useful information for the meta-analysis. Effect sizes (mean weight change in treatment versus control group) were computed and aggregated based on a random-effects model. The influence of several moderators on the effect sizes was examined.  Results. Catechins significantly decreased body weight and significantly maintained body weight after a period of WL (^m¼_1.31 kg; Po0.001). Inhibition of this effect by high habitual caffeine intake (4300mg per day) failed to reach significance (^m¼_0.27 kg for high and ^m¼_1.60 kg for low habitual caffeine intake; P¼0.09). Also, the seemingly smaller effect of catechins in Caucasian (^m¼_0.82 kg) subjects compared with Asians (^m¼–1.51 kg; P¼0.37) did not reach significance.  Interaction of ethnicity and caffeine intake was a significant moderator (P¼0.04).  Conclusions. Catechins or an epigallocatechin gallate (EGCG)–caffeine mixture have a positive effect on WL and WM. The results suggest that habitual caffeine intake and ethnicity may be moderators, as they may influence the effect of catechins.  International Journal of Obesity (2009) 33, 956–961

“This meta-analysis or review of literature was most helpful for establishing a baseline of EGCG’s necessary for weight loss.  As you read this particular study, you’ll see that the average amount was right around 500 mg per day.  Two of the studies gave participants more than 1,000 mg of EGCG per day and found that there was no added benefit for weight loss to having more than 1,000 mg of EGCG per day.   An interesting insight from the analysis is that getting the right amount every day is more powerful than trying to over-consume in a short period of time.  The take home message here is get the right amount of EGCG’s, but do it every day.”  – Josh Smith

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