Hsuan-Yu Wan1, Jonathon L. Stickford1, Emily J. Dawkins2, Alice K. Lindeman2, .... Costill, D. L., Sherman, W. M., Fink, W. J., Maresh, C., Witten, M., & Miller, J.
STORT-TERM CHANGES IN DIETARY PATTERN FOLLOWING GLYCOGEN DEPLETION AND POST-EXERCISE SUPPLEMENTATION 1 Wan ,
1 Stickford ,
2 Dawkins ,
2 Lindeman ,
Hsuan-Yu Jonathon L. Emily J. Alice K. Timothy D. Mickleborough, 1Department of Kinesiology and 2Department of Applied Health, Indiana University, Bloomington, Indiana
INTRODUCTION ▪ When the duration of recovery and access to food are limited, it has been suggested to consume a mixture of carbohydrate and protein (CHO:PRO = 4:1) immediately following strenuous exercise to accelerate muscle glycogen restoration1. ▪ Evidence has been shown that high-intensity exercise has no influence on subsequent food choices in non-athletes up to 48 hours such that exercise-induced energy deficits are not rectified2. ▪ Since subjects’ training status may affect the ability to adjust dietary intake for energy balance3, what remains to be determined is the relation among intense exercise, dietary supplementation, and athletes’ dietary behavior.
PURPOSE
(A) 100%
METHODS ▪ Trained, male cyclists (N = 12; age: 21.7 ± 1.8 y; V̇O2max: 63.0 ± 4.1 ml·kg-1·min-1) performed a glycogen-depleting exercise bout followed by a 2h supplementation period, and 28 h of free-living recovery on two separate occasions. ▪ During 2-h supplementation, subjects consumed equal volume of reduced-fat chocolate milk (2.0 g of CHO·kg-1, 0.5 g of PRO·kg-1) or a sports beverage (0.8 g of CHO·kg-1, 0 g of PRO·kg-1) in a single-blind, randomized design. ▪ Following supplementation, subjects completed a food log during 28-h recovery. Logs were reviewed and analyzed by a registered dietitian.
Calories
75%
75%
50%
50%
100%
During Free-Living Recovery Beverage
100%
FAT
75%
75%
50%
50%
25% 100%
Calories *
75%
PRO
Sports Beverage
Energy (kcal∙kg-1)
63.6 ± 2.9
68.3 ± 4.3
Carbohydrate (g∙kg-1)
8.0 ± 0.5
8.5 ± 0.5
Fat (g∙kg-1)
2.4 ± 0.1
2.5 ± 0.2
Protein (g∙kg-1)
2.6 ± 0.2
2.9 ± 0.3
Total Dietary Intake (Supplement + Free-Living Diets)
0%
*
0% 2H
4H
6H
8H
10H
12H
2H
4H
6H
8H
10H
12H
(B) 50%
50%
25%
25%
CHO
75%
50%
Calories
50%
40%
40%
30%
30%
20%
20%
10%
10%
0%
0%
CHO
Chocolate Milk
Sports Beverage
Energy (kcal∙kg-1)
74.4 ± 2.8
71.3 ± 4.2
Carbohydrate (g∙kg-1)
10.0 ± 0.5
9.3 ± 0.5
Fat (g∙kg-1)
2.5 ± 0.1
2.5 ± 0.2
Protein (g∙kg-1)
3.1 ± 0.2
2.9 ± 0.3
25%
0%
Note. Values are mean ± SEM.
0%
100%
FAT
75%
PRO
50%
25%
25%
0%
CONCLUSIONS
*
75%
50%
50%
FAT
50%
40%
40%
30%
30%
20%
20%
10%
10%
PRO
0% 2H
4H
6H
8H
10H
12H
2H
4H
6H
8H
10H
12H
(B) 50%
Chocolate Milk
Beverage
(A) 100%
Table 2. Composition of Subjects' Diets (analyzed using MyPyramidTracker, USDA, http://www.mypyramidtracker.gov/)
0%
0%
RESULTS
CHO
Joel M. Stager,
1 FACSM
25%
25%
100%
To examine the potential modification of daily energy and macronutrient intakes following muscle glycogen-depleting exercise and specific postexercise refueling treatments.
100%
1 FACSM ,
50%
Calories
*
40%
40%
30%
30%
*
20%
CHO
*
0%
10%
0%
0%
50%
50%
FAT
PRO
*
40%
30%
30%
Beverage
20%
20%
10%
10%
0% 1st 2H
2nd 2H
3rd 2H
4th 2H
5th 2H
6th 2H
3rd 2H
4th 2H
5th 2H
6th 2H
1st 2H
2nd 2H
3rd 2H
4th 2H
5th 2H
6th 2H
Table 1. Nutritional Content of Post-Exercise Recovery Beverages
40%
0%
2nd 2H
Figure 2. Dietary intake relative to the total amount consumed during the 12 hours of free-living recovery prior to the end of recovery. (A) Dietary data are retrospectively accumulated every 2 hours prior to the end of recovery (0H). (B) Dietary data are separated by every 2 h prior to the end of recovery (0H). No difference between the treatments at any time point. Error bars indicate SEM.
20%
10%
0% 1st 2H
1st 2H
2nd 2H
3rd 2H
4th 2H
5th 2H
6th 2H
Figure 1. Dietary intake relative to the total amount consumed during the first 12 hours of free-living recovery. (A) Dietary data are accumulated every 2 h following the end of supplementation (0H). (B) Dietary data are separated by every 2 h following the end of supplementation (0H). Data at each time point are compared between the treatments using paired t-test. * indicates significant difference between the treatments, p < 0.05. Error bars indicate SEM.
Chocolate Milk
Sports Beverage
Volume (ml)
1020.3 ± 35.3
1020.3 ± 35.3
Energy (kcals)
765.2 ± 26.5
212.6 ± 7.4*
Carbohydrate (g)
140.3 ± 4.9
59.5 ± 2.1*
Protein (g)
38.3 ± 1.3
0.0 ± 0.0*
Fat (g)
10.6 ± 0.4
0.0 ± 0.0*
Sodium (mg)
807.7 ± 27.9
467.6 ± 16.2*
Potassium (mg)
1794.0 ± 62.1
127.5 ± 4.4*
Note. Values are mean ± SEM. *Significantly different from chocolate milk (P < 0.05).
▪ Athletes’ free-living diet, in terms of caloric and macronutrient intakes, is modified according to the post-exercise recovery drink content when muscles are depleted of glycogen. ▪ Athletes’ dietary choices during free-living recovery appear sufficient to replenish muscle glycogen4, which may wash out the expected macronutrient benefits of chocolate milk. ▪ Athletes are able to quickly respond to the glycogen depletion and energy deficiency from a fatiguing exercise bout and subsequent refueling supplement through food consumption.
REFERENCES 1. Karp, J. R., Johnston, J. D., Tecklenburg, S., Mickleborough, T. D., Fly, A. D., & Stager, J. M. (2006). Chocolate milk as a post-exercise recovery aid. International Journal of Sport Nutrition & Exercise Metabolism, 16(1), 78-91. 2. King, N. A., Lluch, A., Stubbs, R. J., & Blundell, J. E. (1997). High dose exercise does not increase hunger or energy intake in free living males. European journal of clinical nutrition, 51(7), 478-483. 3. Long, S. J., Hart, K., & Morgan, L. M. (2002). The ability of habitual exercise to influence appetite and food intake in response to high-and low-energy preloads in man. British Journal of Nutrition, 87(05), 517-523. 4. Costill, D. L., Sherman, W. M., Fink, W. J., Maresh, C., Witten, M., & Miller, J. M. (1981). The Role of Dietary Carbohydrates in Muscle Glycogen Resynthesis after Strenuous Running. American Journal of Clinical Nutrition, 34(9), 1831-1836.
