Green tea is a popular weight-loss supplement that also improves blood sugar regulation and influences fat cell turnover. While it is not a magic bullet that instantly improves metabolic health, it helps. Kevin Maki from the Provident Clinical Research, in Bloomington, Indiana showed decreases in total abdominal fat, subcutaneous abdominal fat (under the skin), and blood triglycerides (blood fats) in people consuming a green tea beverage containing 625 mg of catechins and 39 mg of caf¬feine for 12 weeks, compared to a placebo (green tea without catechins or caffeine). The people also did 180 minutes per week of moderate-intensity exercise.
Caffeine and catechins— particularly epigallocatechin-3-gallate— speed metabolism and fight fat. Other studies found that green tea extract increased the conversion of testosterone to estrogen in fat cells, which might have negative effects in body¬builders. Green tea is an effective fat fighter that complements the effects of exercise. However, bodybuilders should use it with caution.