The investigators randomly assigned green tea extract, fermented green tea extract, or placebo in adult subjects whose BMI was 25-35 kg/m2. Participants were 40 in each group, and treatment duration was 12 weeks. Primary outcomes were body weight change and fat mass change from baseline to 12 weeks, and secondary outcomes were metabolic parameteres and gut microbiota.

After screening obese subjects who met the inclusion and exclusion criteria, the investigators randomly assigned the two treatment arms and one placebo arm at 1:1:1 ratio. At baseline, anthropometric and biochemical evaluations were conducted including body weight, body composition (DXA and Fat CT), lipid profiles, and liver function test. The tablets were supplied to each participants under double-blind conditions. The investigators obtained blood and stool samples both baseline and final visit at 12 weeks. For improving compliance for treatments, the investigators checked diary for lifestyle and drug compliance every 6 week.

Inclusion Criteria:

• Age 20-60 years
• BMI 25-35 kg/m2
• Abdominal obesity (Waist circumference): Male >90 cm, Female >85cm

Exclusion Criteria:

• Cardiovascular events within 3 months
• uncontrolled hypertension (>160/100 mmHg)
• Diabetes mellitus
• Dyslipidemia under statin therapy
• TSH<0.1 uU/ml or>10 uU/ml
• Elevated creatinine level (twice higher than upper normal limit)
• Elevated AST/ALT level (three times higher than upper normal limit)
• Pregnancy, lactation