Randomised blinded controlled trials (RCTs) that compared catechins (in green tea or capsules) with no catechins (or different doses of catechins) on weight loss and weight maintenance for at least 12 weeks were eligible for inclusion. Trials that evaluated teas or capsules that contained a mixture of epigallocatechin gallate and caffeine were included. Trials that evaluated other types of teas (for example, oolong tea) were excluded.
The baseline body mass index of trial participants varied from 18.5 to 35kg/m2. Studies generally included both males and females. It appeared that the youngest trial participants were 16 years old and the oldest were 65. The studies mostly included Asian participants (Japanese, Thai, Taiwanese and Chinese); four studies were conducted in Caucasian participants. The dosage of tea consumed that contained an epigallocatechin gallate-caffeine mixture ranged from 270mg per day to 1,207mg per day across studies. Study duration ranged from 12 to 13 weeks. In all weight loss trials, randomisation occurred after a four-week low-energy diet.
It appeared that one reviewer performed the selection.