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

WESTERTERP-PLANTENGA, MARGRIET S.,MANUELA P.G.M. LEJEUNE, AND EVA M. R. KOVACS.  Obes Res. 2005;13:1195–1204.

Abstract:  Investigation of the effect of a green tea-caffeine mixture on weight maintenance after body weight loss in moderately obese subjects in relation to habitual caffeine intake.Research Methods and Procedures: A randomized placebo- controlled double blind parallel trial in 76 overweight and moderately obese subjects, (BMI, 27.5 _ 2.7 kg/m2) matched for sex, age, BMI, height, body mass, and habitual caffeine intake was conducted. A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance (WM); during the WM period, the subjects received a green tea-caffeine mixture (270 mg epigallocatechin gallate _ 150 mg caffeine per day) or placebo. Results: Subjects lost 5.9 _1.8 (SD) kg (7.0 _ 2.1%) of body weight (p _ 0.001). At baseline, satiety was positively,and in women, leptin was inversely, related to subjects’ habitual caffeine consumption (p _ 0.01). High caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers; resting energy expenditure was reduced less and respiratory quotient was reduced more during weight loss (p _ 0.01). In the low caffeine consumers, during WM, green tea still reduced body weight, waist, respiratory quotient and body fat,whereas resting energy expenditure was increased compared with a restoration of these variables with placebo (p _0.01). In the high caffeine consumers, no effects of the green tea-caffeine mixture were observed during WM. Discussion: High caffeine intake was associated with weight loss through thermogenesis and fat oxidation and with suppressed leptin in women. In habitual low caffeine consumers, the green tea-caffeine mixture improved WM, partly through thermogenesis and fat oxidation.

“Regular consumption of green tea provides a thermogenic affect for weight loss and weight maintenance.  A highlight from this study is the evidence of the use of EGCG as a thermogenic aid.  A thermogenic aid is something that wastes energy in the form of heat, instead of producing energy for the body.  The key to long term success with body weight is having a plan to maintain the progress we make through diet and exercise!” - Josh Smith