Objective: To determine whether or not aspirin further potentiates the greater post-prandial thermogenesis induced by ephedrine with caffeine.
Design: Determination of the acute metabolic rate response to the following treatments: 1050 kJ liquid meal (M); meal plus ephedrine (30 mg) and caffeine (100 mg) (MEC) or meal plus ephedrine, caffeine and aspirin (300 mg) (MECA).
Subjects: Lean, pre-disposed obese and obese women (n = 10 each group).
Measurements: Pre- and post-treatment metabolic rate determinations via indirect calorimetry. Post-treatment measurements made at 20 min intervals for a total of 160 min.
Results: In all groups, metabolic rate increased significantly more following the MEC or MECA, compared to the meal only (p < 0.05). The obese group had a significantly greater absolute increase in metabolic rate following the MECA and MEC compared to both the lean and pre-disposed obese groups (p < 0.05). Metabolic rate remained elevated at the end of the 160 min following all treatments.
Conclusion: Aspirin does not further potentiate the acute thermic effect of ephedrine and caffeine with a meal. However, the full thermogenic response was not measured and longer duration studies are necessary to confirm these results.