An optimal nutrient intake not only helps you maximise physical performance, it can also minimise any muscle damage (1). Each macronutrient has a specific role especially before a workout, the ratio in which you consume them will vary depending on the individual and the kind of exercise they are about to undertake (2).
Carbohydrate Consumption and Exercise
Muscles use glucose from carbohydrates to make fuel and your body processes and stores glucose in the form of glycogen found in the liver and muscles. For both low and high intensity exercise, your glycogen stores are your muscles main source of energy (3). However for longer workout sessions, the degree to which glucose is used from the carbohydrates is dependent on several factors such as the intensity, type of workout and overall diet (3).
As your muscles glycogen stores are limited, when the stores become depleted the output and intensity also end up diminishing (4, 5). There is a consistent amount of research which shows that carbohydrates can increase glycogen stores and utilisation along with boosting carbohydrate oxidation during exercise (6, 7, 8).
Carbohydrate loading, is thepractise which involves consuming a high-carb diet for anything up to one week before a competition or exercise bout and is a well-known and understood method which can maximise body stores of glycogen (7, 8).
Experts recommended that consuming 0.6 to 1.0 g/kg body mass within the first 30 min of completing a glycogen depleting exercise bout and again every two hours for the next four to six hours to allow for proper re-synthesis of glycogen (9).
Glycogen synthesis which is influenced by insulin secretion can be better stimulated when both carbohydrates and protein are consumed together after exercising (10, 11, 12).
Protein Consumption and Exercise
There are numerous studies which document the potential that protein consumption has on improving athletic performance, both before and after exercising.
Improved anabolic response and muscle growth (13, 14)
Improved muscle recovery (14)
Increased muscle protein synthesis (13, 15, 16).
Increased amounts of strength and lean body mass (17)
Increased muscle performance (13, 14, 17)
As exercise can trigger the breakdown of muscle protein, by consuming an adequate amount of protein after working out you can provide your body with the amino acids it requires to repair and rebuild proteins and new muscle tissues (18, 19)
Ingesting 20g to 40g of protein after a workout seems to maximise the body’s ability to recover optimally after exercise (20, 21).
The Importance Of Timing
Studies show that your body’s ability to rebuild its glycogen stores and use protein is generally enhanced right after you exercise (21) and for this reason experts recommend that you eat a post-workout meal which contains both carbohydrates and proteins within forty five minutes of exercising. Interestingly, it is also believed that delaying carbohydrate consumption by just two hours after exercising can lead to a fifty percent decrease in the rates of glycogen synthesis (10, 21).
However, if you ate a good well-balanced meal before working out, research does suggest that the benefits from this earlier meal will still apply after your training (15, 16, 21).
It is also importantto make sure that you drink plenty of water both before and after a workout and remain properly hydrated, as during exercise you end up losing a lot of water and electrolytes through sweat. By replenishing fluids and electrolytes after exercising you aid your body’s recovery and performance (22).
For more information on combining nutrition and exercise, see our nutrition for sport and exercise course.
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2. Kerksick, C., Harvey, T., Stout, J., Campbell, B., Wilborn, C., Kreider, R., Kalman, D., Ziegenfuss, T., Lopez, H., Landis, J. and Ivy, J.L., 2008. International Society of Sports Nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition, 5(1), p.17.
3. Gollnick, P.D. and Matoba, H., 1984. Role of carbohydrate in exercise. Clinics in sports medicine, 3(3), pp.583-593.
4. Coyle, E.F., Coggan, A.R., Hemmert, M.K. and Ivy, J.L., 1986. Muscle glycogen utilization during prolonged strenuous exercise when fed carbohydrate. Journal of applied physiology, 61(1), pp.165-172.
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6. Tarnopolsky, M.A., Gibala, M., Jeukendrup, A.E. and Phillips, S.M., 2005. Nutritional needs of elite endurance athletes. Part I: Carbohydrate and fluid requirements. European Journal of Sport Science, 5(1), pp.3-14.
7. Bussau, V.A., Fairchild, T.J., Rao, A., Steele, P. and Fournier, P.A., 2002. Carbohydrate loading in human muscle: an improved 1 day protocol. European journal of applied physiology, 87(3), pp.290-295.
8. Goforth Jr, H.W., Laurent, D., Prusaczyk, W.K., Schneider, K.E., Petersen, K.F. and Shulman, G.I., 2003. Effects of depletion exercise and light training on muscle glycogen supercompensation in men. American Journal of Physiology-Endocrinology and Metabolism, 285(6), pp.E1304-E1311.
9. Kerksick et al 2017. International society of sports nutrition position stand: nutrient timing. J Int Soc Sports Nutr 14(1), p33.
10. Poole, C., Wilborn, C., Taylor, L. and Kerksick, C., 2010. The role of post-exercise nutrient administration on muscle protein synthesis and glycogen synthesis. Journal of sports science & medicine, 9(3), p.354.
11. Ivy, J.L., 1998. Glycogen resynthesis after exercise: effect of carbohydrate intake. International journal of sports medicine, 19(S 2), pp.S142-S145.
12. Biolo, G., Williams, B.D., Fleming, R.Y. and Wolfe, R.R., 1999. Insulin action on muscle protein kinetics and amino acid transport during recovery after resistance exercise. Diabetes, 48(5), pp.949-957.
13. Willoughby, D.S., Stout, J.R. and Wilborn, C.D., 2007. Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength. Amino acids, 32(4), pp.467-477.
14. Kraemer, W.J., Hatfield, D.L., Spiering, B.A., Vingren, J.L., Fragala, M.S., Ho, J.Y., Volek, J.S., Anderson, J.M. and Maresh, C.M., 2007. Effects of a multi-nutrient supplement on exercise performance and hormonal responses to resistance exercise. European journal of applied physiology, 101(5), pp.637-646.
15. Tipton, K.D., Elliott, T.A., Cree, M.G., Aarsland, A.A., Sanford, A.P. and Wolfe, R.R., 2007. Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise. American Journal of Physiology-Endocrinology and Metabolism, 292(1), pp.E71-E76.
16. Tipton, K.D., Rasmussen, B.B., Miller, S.L., Wolf, S.E., Owens-Stovall, S.K., Petrini, B.E. and Wolfe, R.R., 2001. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. American Journal of Physiology-Endocrinology And Metabolism, 281(2), pp.E197-E206.
17. Cribb, P.J. and Hayes, A., 2006. Effects of supplement-timing and resistance exercise on skeletal muscle hypertrophy. Medicine & Science in Sports & Exercise, 38(11), pp.1918-1925.
18. Biolo, G., Tipton, K.D., Klein, S. and Wolfe, R.R., 1997. An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein. American Journal of Physiology-Endocrinology And Metabolism, 273(1), pp.E122-E129.
19. Kreider, R.B. and Campbell, B., 2009. Protein for exercise and recovery. The Physician and sportsmedicine, 37(2), pp.13-21.
20. Tipton, K.D., Ferrando, A.A., Phillips, S.M., Doyle Jr, D. and Wolfe, R.R., 1999. Postexercise net protein synthesis in human muscle from orally administered amino acids. American Journal of Physiology-Endocrinology And Metabolism, 276(4), pp.E628-E634.
21. Aragon, A.A. and Schoenfeld, B.J., 2013. Nutrient timing revisited: is there a post-exercise anabolic window?. Journal of the international society of sports nutrition, 10(1), p.5.
22. Convertino, V.A., Armstrong, L.E., Coyle, E.F., Mack, G.W., Sawka, M.N., Senay, J.L. and Sherman, W.M., 1996. American College of Sports Medicine position stand. Exercise and fluid replacement. Medicine and science in sports and exercise, 28(1), pp.i-vii.