Trained male cyclists (n=11;24.3 ± 0.6 years; VO2MAX:54.9 ± 2.7ml/kg/min)consumed isocaloricsports beverages containing citric acid (placebo), triacetin (TRI), or acetic acid (AA)in a double-blind, randomized, controlled crossover study. Subjects consumed 710 mLbeverage anda standard breakfastbeginning each test day. Subjects performed two 30 second Wingate cycle tests separated by 4 minutes and consumed 7.5 ml/kg beveragewhile resting during a 60-min recovery period. Subjects then cycled for three 15-min consecutive segments at 65% VO2MAX followed by a 15-min simulated “time trial.” Three ml/kg beverage was consumed during the endurance cycle test. Plasma glucose and lactate; serum free fatty acids, sodium, potassium, chloride, bicarbonate, osmolality; whole blood pH, urine osmolality and specific gravity were obtained at timesthroughout the day to assess markers of metabolism, and respiratory and cardiovascular variables were assessed during the time trial. Data were analyzed using repeated measures analysis of variance including subject and treatment as factors; Tukey’s test was used for pairwise comparisons. Data are presented as means ± SEM and p < 0.05 was considered significant.