THERMOGENIC EFFECT AND BODY COMPOSITION CHANGES WITH WEIGHT LOSS SUPPLEMENT IN OBESE ADULTS

Abstract

The purpose of the study was to examine the effects of a commercially available herbal mixture containing several potential thermogenic botanicals, including: ma huang (ephedrine), bitter orange (synephrine) and guarana extract (caffeine), on resting energy expenditure relative to body weight (REE) and body composition in obese adults. Fifteen females and 5 males (age = 31.0 ± 6.6 yr, height = 168.1 ± 8.4 cm, weight = 93.4 ± 17.1 kg, %fat = 43.8 ± 6.5%) participated. The study was approved by the Human Subjects Review Committee and informed consent was obtained. Subjects were matched according to age, gender, height, weight, and body fat and randomly assigned to receive 2 capsules of either supplement (XEN, N = 12) or placebo (N = 8) twice daily for 6 weeks. In addition, subjects participated in a 44 d aerobic exercise program (3 d/wk). Exercise sessions involved walking/jogging 1.5 mi at a brisk, but comfortable pace the first two sessions and 2.0 mi each remaining session. Pre- and post-treatment measures were taken of resting energy expenditure using open-circuit spirometry, and three-compartment body composition using DEXA. Statistical analysis of the percent change in REE, body mass (BM), %Fat, fat mass (FM), and fat-free mass (FFM) using independent t-tests revealed a significant change at α 0.05 in FM only (P = 0.033, β-1 = 0.033, β-1 = 0.587). Power was determined to be low (β-1 = 0.067 to 0.587). A more liberal statistical approach (α 0.10), however, indicated that %Fat and BM were significant (P = 0.096 and 0.087, respectively) and power increased (β-1 = 0.518, 0.539. and 0.716 for %Fat, BM, and FM, respectively). These data suggest that daily supplementation with XEN may result in reductions in FM, %Fat and BM in obese subjects during aerobic exercise training. Supported by a grant from Phoenix Laboratories.