Summary of findings for the main comparison. Green tea for overweight or obese adults.

Green tea for overweight or obese adults
Patient or population: overweight or obese adults Settings: primary care and research centres Intervention: green tea preparations Comparison: placebo
Outcomes	Illustrative comparative risks* (95% CI)		Relative effect (95% CI)	No of participants (studies)	Quality of the evidence (GRADE)	Comments
	Assumed risk	Corresponding risk
	Control	Green tea
All‐cause mortality	See comment	See comment	Not estimable	See comment	See comment	Not investigated
Morbidity	See comment	See comment	Not estimable	See comment	See comment	Not investigated
Health‐related quality of life	See comment	See comment	Not estimable	See comment	See comment	Not investigated
Patient satisfaction	See comment	See comment	Not estimable	See comment	See comment	Not investigated
Adverse effects 12 to 13 weeks follow‐up	See comment	See comment	Not estimable	See comment	⊕⊝⊝⊝ very low1	6 studies did not report on the presence or absence of adverse events, 8 reported that there were none and 4 reported the presence of adverse events. Most adverse effects, such as nausea, constipation, abdominal discomfort and increased blood pressure, were judged to be mild to moderate
Weight loss (change in kg) 12 to 13 weeks follow‐up	The mean weight loss in the control groups ranged from 4.2 kg lost to 0.08 kg gained	The mean weight loss in the intervention groups was 0.04 kg greater	‐0.04 (0.5 to 0.43)	532 (6 studies)	⊕⊕⊕⊝ moderate2	Although there was a very small effect with green tea compared to control, it was not statistically significant and may not be clinically relevant
Costs	See comment	See comment	Not estimable	See comment	See comment	Not reported
*The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval.
GRADE Working Group grades of evidence High quality: Further research is very unlikely to change our confidence in the estimate of effect. Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate. Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate. Very low quality: We are very uncertain about the estimate.

¹Short follow‐up and non‐systematic reporting of adverse effects.

²Downgraded one level because all six studies were assessed as having unclear risk of bias in at least one domain. Five of six studies had random sequence generation assessed as unclear risk of bias. Four of six had both allocation concealment and blinding assessed as unclear risk of bias.