Weight loss and weight maintenance with green tea supplementation

Nutrition Research Newsletter, Sept, 2005 by M. Westerterp-Plantenga, M. Lejeune, E. Kovacs

With the increased incidence of obesity comes an increased risk of a number of diseases, including coronary heart diseases, hypertension, noninsulin-dependent diabetes, pulmonary dysfunction, osteoarthritis, and certain forms of cancers. Treatment of obesity is beneficial in that weight loss reduces the risk for mortality and morbidity. Even a modest weight loss of 5% to 10% of initial body weight shows beneficial health effects. Modest weight loss is a realistic goal for most individuals. However, long-term maintenance of body weight loss tends to be unsuccessful. Interventions to improve long-term weight maintenance are needed to treat obesity effectively.

A fast growing therapeutic area is the use of natural herbal supplements. One of these agents is a green tea-caffeine mixture (epigallocatechin gallate plus caffeine), whose claimed antiobesity properties have been ascribed to increased thermogenesis and fat oxidation.

Based on studies in humans, it was hypothesized that a green tea-caffeine mixture would reduce body weight regain in humans after weight loss, possibly through a thermogenic effect. A study was conducted on body weight maintenance with the aim of investigating whether the same green tea-caffeine mixture may improve weight maintenance by preventing or limiting weight regain after weight loss of 5% to 10% in moderately obese subjects with a low or high habitual caffeine intake.

Seventy-six overweight and moderately obese individuals, aged 18 to 60 years, served as subjects. The subjects were divided into two stratified groups according to sex, BMI, age, dietary restraint, resting energy expenditure (REE), and being either habitual low caffeine consumers or habitual high caffeine consumers. A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance (WM). During the WM period, the subjects received a green tea-caffeine mixture (270 mg epigallocatechin gallate 150 mg caffeine per day) or placebo.

Subjects lost 5.9 1.8 (SD) kg (7.0 [ or -] 2.1%) of body weight (p < 0.001). At baseline, satiety was positively, and in women, leptin was inversely related to subjects' habitual caffeine consumption (p < 0.01). High caffeine consumers reduced weight, fat mass, and waist circumference more than low caffeine consumers; REE was reduced less and respiratory quotient was reduced more during weight loss (p < 0.01). In the low caffeine consumers, during WM, green tea still reduced body weight, waist, respiratory quotient and body fat, whereas REE was increased compared with a restoration of these variables with placebo (p < 0.01). In the high caffeine consumers, no effects of the green tea-caffeine mixture were observed during WM.

High caffeine intake was found to be associated with weight loss through thermogenesis and fat oxidation in women. Caffeine intake was also found to suppress leptin in women. In the subjects who had habitually low caffeine intake, the green tea-caffeine mixture improved WM, partly through thermogenesis and oxidation.

M. Westerterp-Plantenga, M. Lejeune, E. Kovacs. Body weight loss and weight maintenance in relation to habitual caffeine intake and green tea supplementation. Obes Res; 13:1195-1204 (July, 2005). [Correspondence: Margriet S. Westerterp-Plantenga, Department of Human Biology, Maastricht University, PO Box 616, NL-6200 MD Maastricht, Netherlands. E-mail: m.westerterp@hb.unimaas.nl]