The Anti-Obesity Effects of Green Tea: A Controlled, Randomized, Clinical Trial

Background: Obesity is a global health threatening issue with increasing prevalence in the developed and developing world. The limited efficacy and side effects of conventional treatments motivated the researchers to look for novel, safe, and effective therapeutic strategies. Objectives: The current study aimed at investigating the anti-obesity effects of green tea in a population in North of Iran. Methods: The current single-blind, placebo-controlled, parallel, clinical trial was conducted in Guilan outpatient clinic in Rasht, Iran, from January to December 2015. Eligible subjects were randomly allocated into 2 groups of green tea and control. In the GT Group, a cup of green tea and in the C group an equal amount of mineral water was taken 30 minutes after breakfast and lunch. The outcomes including body weight (BW), body mass index (BMI), hip circumference, waist circumference, and waist-to-hip ratio were measured at baseline, as well as 8 and 12 weeks after the intervention (T0, T_1, T_2). Results: Finally, data obtained from 84 cases in groups GT (n = 41) and C (n = 43) were analyzed. No significant difference was observed in terms of baseline demographics and measurements between the 2 groups including male/female (P = 0.766), age (P = 0.376), weight (P = 0.846), height (P = 0.413), waist circumference (P = 0.619), hip circumference (P = 0.619), and waist-to-hip ratio (P = 0.301). According to the intragroup analyses, the trend of changes from baseline to 12 weeks after intervention were significant in both groups (P = 0.001); BW (79.88 +/- 7.06 to 72.44 +/- 6.82 kg) and (80.21 +/- 7.16 to77.07 +/- 7.22 kg), BMI (29.95 +/- 1.79 to 26.86 +/- 2.59 kg/m(2)) and (29.69 +/- 2.1 to 27.07 +/- 2.22 kg/m(2)), waist circumference (87.77 +/- 6.06 to 83.913 +/- 6.13 cm) and (86.94 +/- 8.05 to 85.23 +/- 7.89 cm), and hip circumference (102.41 +/- 7.35 to 98.3 +/- 7.54 cm) and (101.02 +/- 8.47 to 99.31 +/- 8.81 cm) in GT and C groups, respectively. However no such difference was observed in waist/hip ratio in the GT and C groups (P = 0.087) and (P = 0.322), respectively. A significant difference was observed at T1 (P = 0.024 and P = 0.025) and T2 (P = 0.025 and P = 0.006), according to weight and BMI, respectively. However, the differences were not statistically significant based on the other variables. Conclusions: Green tea could be a safe and effective choice for patients with obesity. However, further well-designed trials are required to confirm these findings.