King Grub
2017-11-23, 10:30
PURPOSE:
To determine the impact of pre-exercise carbohydrate of different glycemic indices on subcutaneous abdominal adipose tissue (SCAAT) metabolism and running performance.
METHODS:
Ten trained male runners completed three experimental trials consisting of 30 min at 60% VO2max, 30 min at 75% VO2max, and a 5-km time trial (TT). Thirty min prior to exercise, participants consumed one of three beverages: 1) 75 g low glycemic index modified starch supplement (UCAN), 2) 75 g high glycemic index glucose-based supplement (G), or 3) a flavor-matched non-caloric placebo (PL). SCAAT lipolysis was assessed via microdialysis.
RESULTS:
Prior to exercise, blood glucose and insulin were elevated with G vs. PL (+53.0 ± 21.3 mg[BULLET OPERATOR]dL [SD]; p < 0.0001; +33.9 ± 11.0 μU[BULLET OPERATOR]mL; p < 0.0001) and G vs. UCAN (+36.6 ± 24.9 mg[BULLET OPERATOR]dL; p < 0.0001; +25.2 ± 11.0 μU[BULLET OPERATOR]mL; p < 0.0001), respectively. Fat oxidation was attenuated, and carbohydrate oxidation increased prior to exercise with G vs. PL (-0.06 ± 0.06 g[BULLET OPERATOR]min; p = 0.005; +0.18 ± 0.07 g[BULLET OPERATOR]min; p < 0.0001) and G vs. UCAN (-0.06 ± 0.05 g[BULLET OPERATOR]min; p = 0.004; +0.18 ± 0.14 g[BULLET OPERATOR]min; p < 0.0001). However, there were no differences in SCAAT lipolysis at rest or during running at either exercise intensity. Also, there was no effect of treatment on running performance.
CONCLUSIONS:
Pre-exercise carbohydrate lowers fat oxidation and increases carbohydrate oxidation, and these effects are attenuated with low glycemic index carbohydrate. However, these changes are not the result of alterations in SCAAT lipolysis, nor do they affect running performance.
PMID: 29166321
Med Sci Sports Exerc. 2017 Nov 20. Adipose Lipolysis Unchanged by Preexercise Carbohydrate regardless of Glycemic Index.
To determine the impact of pre-exercise carbohydrate of different glycemic indices on subcutaneous abdominal adipose tissue (SCAAT) metabolism and running performance.
METHODS:
Ten trained male runners completed three experimental trials consisting of 30 min at 60% VO2max, 30 min at 75% VO2max, and a 5-km time trial (TT). Thirty min prior to exercise, participants consumed one of three beverages: 1) 75 g low glycemic index modified starch supplement (UCAN), 2) 75 g high glycemic index glucose-based supplement (G), or 3) a flavor-matched non-caloric placebo (PL). SCAAT lipolysis was assessed via microdialysis.
RESULTS:
Prior to exercise, blood glucose and insulin were elevated with G vs. PL (+53.0 ± 21.3 mg[BULLET OPERATOR]dL [SD]; p < 0.0001; +33.9 ± 11.0 μU[BULLET OPERATOR]mL; p < 0.0001) and G vs. UCAN (+36.6 ± 24.9 mg[BULLET OPERATOR]dL; p < 0.0001; +25.2 ± 11.0 μU[BULLET OPERATOR]mL; p < 0.0001), respectively. Fat oxidation was attenuated, and carbohydrate oxidation increased prior to exercise with G vs. PL (-0.06 ± 0.06 g[BULLET OPERATOR]min; p = 0.005; +0.18 ± 0.07 g[BULLET OPERATOR]min; p < 0.0001) and G vs. UCAN (-0.06 ± 0.05 g[BULLET OPERATOR]min; p = 0.004; +0.18 ± 0.14 g[BULLET OPERATOR]min; p < 0.0001). However, there were no differences in SCAAT lipolysis at rest or during running at either exercise intensity. Also, there was no effect of treatment on running performance.
CONCLUSIONS:
Pre-exercise carbohydrate lowers fat oxidation and increases carbohydrate oxidation, and these effects are attenuated with low glycemic index carbohydrate. However, these changes are not the result of alterations in SCAAT lipolysis, nor do they affect running performance.
PMID: 29166321
Med Sci Sports Exerc. 2017 Nov 20. Adipose Lipolysis Unchanged by Preexercise Carbohydrate regardless of Glycemic Index.