Ever wondered, whether the drink that was once rumored to contain "taurine from bull sperm" and similar fashionable "energy drinks" are of any use? Well, a recent study (
Nienhuesser. 2011) coming from an international team of scientists showed that the consumption of each and every of the three energy drinks used in this study lead to a statistically significant increase in resting metabolic rate (RMR).
[...] in a randomly assigned cross-over design, the subjects consumed 473 ml of one of three commercially available energy drinks or a placebo and then RMR and RER [respiratory exchange ratio; i.e. a measure of the relative amount of fat/carbs that is used as fuel] were measured 1 hour later. The subjects then engaged in 15 minutes of treadmill exercise at 50% of V02max, during which RER and oxygen consumption (VO2) were measured. RMR was not changed by placebo, but increased (P<0.05, means ± se) above baseline by 10 ± 2.5%, 15.0 ± 2.9%, and 15.3 ± 2.9%, following Energy Drink One, Energy Drink Two, and Energy Drink Three (respectively) [...]
In view of the stimulating effect, some of the ingredients (cf. Table 1) of these chemical containing beverages exhibit, these results do not come as a surprise.
What may be surprising, however, is that the study results suggest that - at least from a "calorie expenditure" point of view - the consumption of an energy drink before exercise appears to be less effective than drinking it after exercise or at your desk at the office...