Acute endurance exercise has been shown to lower postprandial plasma triglyceride (PPTG) concentrations; however, whether this is due to the negative energy and/or CHO deficit from the exercise bout is not well understood.
Purpose: This study aimed to examine the effects of a postexercise meal consisting of either high or low CHO content on PPTG and postprandial fat oxidation the morning after an exercise bout.
Methods: Healthy young men (n = 6) performed each of four experimental treatments: 1) nonexercise control (CON), 2) 80 min of cycling with either no meal replacement (EX), 3) a high-CHO postexercise meal (EX+HCHO), or a 4) low-CHO postexercise meal (EX+LCHO). A standardized meal for PPTG determination was provided (16.0 kcal·kg−1 body mass, 1.02 g fat·kg−1, 1.36 g CHO·kg−1, 0.31 g protein·kg−1) 12 h after the exercise, and measurements of plasma triglyceride (TG) concentration and whole-body resting fat oxidation were made in the fasted condition and during the 4-h postprandial period.
Results: The total area under the curve for plasma TG was significantly lower in EX+LCHO (325 (63) mg·dL−1 per 4 h) compared with that in EX+HCHO (449 (118) mg·dL−1 per 4 h, P = 0.03). Postprandial fat oxidation during this period was significantly greater in EX+LCHO (257 (58) kcal per 4 h, P = 0.003) compared with that in EX+HCHO (209 (56) kcal per 4 h). The change in total postprandial fat oxidation (kcal per 4 h) relative to CON was significantly and inversely correlated with the change in the total TG area under the curve relative to CON (mg·dL−1 per 4 h, ΔTG AUC, R2 = 0.37, P = 0.008).
Conclusions: The low CHO composition of the postexercise meal contributes to lower PPTG and increased fat oxidation, with lower PPTG related to an increase in fat oxidation.
Human Performance Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX
Address for correspondence: Edward F. Coyle, Ph.D., Human Performance Laboratory, Department of Kinesiology and Health Education, University of Texas at Austin, One University Station, Bellmont Hall, Room 222K, Austin, TX 78712; E-mail: email@example.com.
Submitted for publication June 2013.
Accepted for publication February 2014.