Abstract
BackgroundThe purpose of this study was to examine the acute effects of a weight loss supplement on resting oxygen uptake (VO2), respiratory quotient (RQ), caloric expenditure (kcal), heart rate (HR), and blood pressure (BP) in healthy and physically active individuals.MethodsTen subjects (5 male, 5 female; 20.2 ± 1.2 y; 172.2 ± 8.9 cm; 71.5 ± 17.2 kg; 17.3 ± 2.6% body fat) underwent two testing sessions administered in a randomized and double-blind fashion. During each session, subjects reported to the Human Performance Laboratory after at least 3-h post-absorptive state and were provided either 3 capsules of the weight loss supplement (SUP), commercially marketed as Meltdown® or 3 capsules of a placebo (P). Subjects then rested in a semi-recumbent position for three hours. VO2 and HR were determined every 5 min during the first 30 min and every 10 min during the next 150 min. BP was determined every 15 min during the first 30 min and every 30 min thereafter. The profile of mood states was assessed every 30 min.ResultsArea under the curve analysis revealed a significant 28.9% difference in VO2 between SUP and P for the three hour study period. In addition, a significant difference in energy expenditure was also seen between SUP (1.28 ± 0.33 kcal·min-1) and P (1.00 ± 0.32 kcal·min-1). A trend (p = 0.06) towards a greater utilization of stored fat as an energy source was also demonstrated (0.78 ± 0.23 kcal·min-1 and 0.50 ± 0.38 kcal·min-1 in P and SUP, respectively). Significant elevations in HR were seen during hours two and three of the study, and significantly higher average systolic BP was observed between SUP (118.0 ± 7.3 mmHg) and P (111.4 ± 8.2 mmHg). No significant differences were seen in diastolic blood pressure at any time point. Significant increases in tension and confusion were seen in SUP.ConclusionResults indicate a significant increase in energy expenditure in young, healthy individuals following an acute ingestion of a weight loss supplement. In addition, ingestion of this supplement appears modify mood and elevate HR and systolic BP following ingestion.
Highlights
The purpose of this study was to examine the acute effects of a weight loss supplement on resting oxygen uptake (VO2), respiratory quotient (RQ), caloric expenditure, heart rate (HR), and blood pressure (BP) in healthy and physically active individuals
Studies examining the thermogenic effect from high-energy supplements are limited, several recent investigations have suggested that the combination of thermogenic agents in a supplement may be more effective in increasing the thermogenic effect than a single herbal ingredient [5,6]
A significant difference (p = 0.01) in average energy expenditure was seen between SUP (1.28 ± 0.33 kcal·min1) and P (1.00 ± 0.32 kcal·min-1) during the entire 3-hr period
Summary
The purpose of this study was to examine the acute effects of a weight loss supplement on resting oxygen uptake (VO2), respiratory quotient (RQ), caloric expenditure (kcal), heart rate (HR), and blood pressure (BP) in healthy and physically active individuals. A number of herbal ingredients have been proposed as being effective agents in increasing energy expenditure and reducing body fat [4]. Caffeine has been shown to be an effective supplement in enhancing lipolysis, fat oxidation, and reducing glycogen breakdown [7,8], when combined with other thermogenic agents its effectiveness appears to be magnified [5,6]. Recent research has suggested that to maximize the effectiveness of synephrine as an effective weight loss supplement it may need to be combined with other herbal products [13]. Some of these products may include yohimbine, yerba mate extract, hordenine and methyl tetradecylthioacetic acid. All of which have been shown to play a role in enhancing lipolysis and increasing energy expenditure [14,15,16]
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