Green tea is often sold as a metabolism booster. The research is more modest than the marketing. This guide summarises three systematic reviews so you know what size of effect, if any, is realistic.
What the meta-analyses found
A 2009 meta-analysis in the International Journal of Obesity pooled 11 studies and reported that green tea catechins significantly decreased body weight and helped maintain weight after a period of weight loss, with a pooled effect of about 1.31 kg. The authors noted that high habitual caffeine intake (more than 300 mg a day) may blunt the effect, although that difference did not reach statistical significance.
A 2010 meta-analysis of 15 randomised trials (1,243 participants) in the American Journal of Clinical Nutrition found small average reductions with catechins plus caffeine: BMI fell by about 0.55, body weight by about 1.38 kg and waist circumference by about 1.93 cm. Waist-to-hip ratio did not change.
What the Cochrane review concluded
The Cochrane review (2012) looked specifically at overweight and obese adults. For six studies conducted outside Japan, the average difference in weight loss was only -0.04 kg. Studies conducted in Japan varied more, with results ranging from -0.2 kg to -3.5 kg in favour of green tea. The reviewers concluded that green tea preparations appear to cause a small, statistically non-significant weight loss that is unlikely to be clinically important, and no significant effect on maintaining weight loss.
What this means for you
- Green tea is a healthy, low-calorie drink, but treat any weight effect as small.
- Calories, protein, sleep and activity still do most of the work.
- If you are sensitive to caffeine, count the caffeine in your tea toward your daily total.
Frequently asked questions
Does green tea burn belly fat?
The reviews above measured body weight, BMI and waist circumference. The 2010 meta-analysis found a small average reduction in waist circumference of about 1.93 cm with catechins plus caffeine, but the Cochrane review found no clinically important weight loss.
How much weight can green tea help you lose?
Estimates range from around 1.3 to 1.4 kg in the two meta-analyses to almost nothing in the Cochrane analysis of studies outside Japan.
Does green tea help keep weight off?
The 2009 meta-analysis reported a benefit for maintaining weight after weight loss, but the Cochrane review found no significant effect on maintenance.
References
- Hursel R, Viechtbauer W, Westerterp-Plantenga MS (2009). The effects of green tea on weight loss and weight maintenance: a meta-analysis. Int J Obes (Lond). PubMed 19597519
- Phung OJ et al. (2010). Effect of green tea catechins with or without caffeine on anthropometric measures: a systematic review and meta-analysis. Am J Clin Nutr. PubMed 19906797
- Jurgens TM et al. (2012). Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database Syst Rev. PubMed 23235664
General information, not medical advice. Talk to your doctor before changing your diet or exercise routine. Last updated 27 October 2026.
