Tsuchida 2002.

Methods	The study was a randomised, placebo‐controlled, double‐blind trial with a treatment to control randomisation ratio of 1:1.05
Participants	INCLUSION CRITERIA: BMI 24 to 30 kg/m2 male and female EXCLUSION CRITERIA: NR DIAGNOSTIC CRITERIA: height weight BMI (calculated from previous 2 measurements)
Interventions	NUMBER OF STUDY CENTRES: 6 COUNTRY/ LOCATION: Japan/Kodama Central Hospital (Kodama County), Central Hospital (Tokyo), Hiratsuka Gastroenterological Hospital, (Tokyo), Kousei Medical Clinic (Tokyo), Takanashi Clinic (Tokyo) and Isogo Central Neurosurgical Hospital and Health Management Center (Yokohama) SETTING: clinics, hospitals, health management centre TREATMENT BEFORE STUDY: note: 2‐week run‐in period
Outcomes	OUTCOME(S) (as stated in the protocol/registered trial documents): PRIMARY OUTCOME(S): unknown SECONDARY OUTCOME(S): unknown OTHER OUTCOME(S): unknown
Study details	STUDY TERMINATED BEFORE REGULAR END: no
Publication details	This study was published in Japanese in the journal Progress in Medicine and no sources of funding were reported
Stated aim of study	Quote from study: "In the present study, we expanded the scale of investigation so as to verify the effect of catechins on body fat reduction in a participant group that included women"
Notes	BMI: body mass index
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quote from study: "after a two‐week run‐in period, participants at each facility were randomly assigned, male and female by turn, into two groups" Comment: we judged this to be an inappropriate method of randomisation, and at a high risk of bias
Allocation concealment (selection bias)	Unclear risk	Comment: not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote from study: "a double blind study was then conducted over two 12‐week periods..." Comment: no mention of effectiveness of blinding efforts. No mention of whether researchers and staff were blinded to study components
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Comment: all outcomes on which the study reported were objective and measured by assessors. Therefore, whether or not assessors were blinded, risk of detection bias was assessed as low
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Comment: recruitment and randomisation numbers are not given, so it is unclear whether there was any attrition
Selective reporting (reporting bias)	Unclear risk	Comment: authors did not clearly state what they would look for, so it is difficult to be sure that there was not selective reporting
Other bias	Low risk	Comment: appears to be free of other bias