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The effects of green tea on weight loss and weight maintenance: a meta-analysis
Random-effects meta-analysis of 11 English-language trials: green tea catechins (with caffeine) associated with modestly lower mean body weight during weight-loss phases and better weight maintenance versus control; habitual caffeine intake and ethnicity moderated apparent effect sizes.
Design
- Meta-analysis; 11 RCTs meeting inclusion after screening 49 candidate publications
- Model: random-effects aggregation of mean weight change (treatment vs control)
- Exposure: green tea catechins (often with caffeine) vs control
Pooled weight signals (abstract)
- Catechins during weight loss / maintenance: pooled mean treatment advantage about −1.31 kg (P < 0.001) in the abstract’s primary framing
- Moderators: >300 mg/day habitual caffeine associated with smaller pooled signals than ≤300 mg/day (P = 0.09 for difference); ethnicity × caffeine interaction P = 0.04
Evidence hygiene
Small mean effects with moderator heterogeneity—not interchangeable with structured diet or exercise trials; watch GI caffeine side-effects.
Publication
Hursel R, Viechtbauer W, Westerterp-Plantenga MS. Int J Obes (Lond). 2009 Sep;33(9):956-961. doi: 10.1038/ijo.2009.135. PMID 19597519.
Outcomes
- Pooled mean body-weight change favoured catechins versus control by about −1.31 kg (P<0.001) across included weight-loss/maintenance trials in abstract.
- Moderator signals: high habitual caffeine (>300 mg/day) vs low associated with smaller pooled weight effects (between-group P=0.09); ethnicity × caffeine interaction P=0.04.