The Effect of Commercial Dietary Supplement Beverages on Basal Metabolism

Abstract

The obesity epidemic has facilitated some commercial beverage manufactures to include claims for weight loss and caloric expenditure in their advertising. One commercial beverage claims a rise in caloric expenditure of 100 calories within three hours following consumption of the beverage. This purported boost in metabolism would be advantageous for anyone with a positive caloric balance. PURPOSE: The purpose of this study was to evaluate the effects of three commercial beverages on caloric expenditure during a basal metabolic state. METHODS: 8 female and 4 male college-age students (age 21.5 ±1.2 yrs, height 169.4 ±11.1 cm, body mass 67.4 ±14.8 kg) volunteered to participate in a double blind crossover study. Subjects adhered to basal metabolic rate (BMR) conditions and reported to the lab for BMR assessment by open circuit spirometry. Following BMR, subjects randomly ingested 355 mL of beverage (B) 1 (10 kcal CHO, 200 mg caffeine), B2 (15 kcal CHO, 110 mg caffeine), or B3 (placebo; no kcals or caffeine). After ingestion, metabolic rate was measured continuously for 15 of 30 min for 3 hrs. There was a minimum of 7 days between trials. RESULTS: Statistical analysis by ANOVA (p<0.05) revealed a significant, but small, increase in oxygen consumption above BMR for the caffeine containing beverages of B1 for 30 min, and of B2 for 120 min. During the three hour post-ingestion period, the total additional caloric expenditure above BMR was 23.7, 29.3, and 17.1 kcals for B 1, 2, and 3, respectively, with no significant difference among the beverages. CONCLUSION: The subtle increase in caloric expenditure of caffeine and calorie- containing beverages, was not significantly greater than the placebo beverage, thus the thermic effect was similar. The meager thermogenesis above BMR is insufficient for clinical standards of weight loss, and is therefore ineffective as a lone strategy in weight management.