The influence of post-exercise macronutrient intake on energy balance and protein metabolism in active females participating in endurance training.
The purpose of this investigation was to determine the influence of post-exercise macronutrient intake on weight loss, protein metabolism, and endurance exercise performance during a period of increased training volume. Ten healthy young female endurance athletes performed 4 60-min bouts of cycle ergometry at approximately 65% of VO2peak on 4 days (day 1, 3, 4, and 6) during 2 separate 1-week periods. On day 7, participants performed a ride to exhaustion at approximately 75% of VO2peak. One of the 7-day periods served as a control condition, where a placebo beverage was consumed following the exercise bouts on days 1, 3, 4, and 6 (CON). During the other 7-day protocol (POST), participants consumed a predefined formula beverage with added carbohydrate following the exercise bouts on days 1, 3, 4, and 6. Energy intake and macronutrient proportions were the same between the 2 trials; the only difference was the timing at which the macronutrients were consumed. Calculated fat oxidation was greater during exercise on day 6 during POST as compared to CON (p < .05). Glucose and insulin concentrations were significantly higher (p < .05) following exercise during POST as compared to CON. There was a trend (p = .06) for nitrogen balance to be greater on days 5 and 6 with POST as compared to CON. Time to exhaustion during exercise on day 7 was longer during POST as compared to CON (p < .05). POST resulted in a maintenance of body weight during the 7-day protocol, while there was a significant (p < .05) reduction with CON. It was concluded that post-exercise macronutrient intake following endurance exercise can attenuate reductions in body weight and improve nitrogen balance during 7 days of increased energy expenditure. Importantly, post-exercise supplementation improved time to exhaustion during a subsequent bout of endurance exercise.
Departments of Medicine and Kinesiology, McMaster University, Hamilton, ON, Canada L8N 3Z5.
Brian D
BD
Roy
Katherine
K
Luttmer
Michael J
MJ
Bosman
Mark A
MA
Tarnopolsky
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight / Q000502:physiology; D003404:Creatinine / Q000652:urine; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage* / Q000378:metabolism*; D002149:Energy Intake / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D019344:Lactic Acid / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D013997:Time Factors
D001786:Blood Glucose; D004044:Dietary Proteins; D007328:Insulin; D019344:Lactic Acid; D003404:Creatinine