The Role of Adding Carbohydrate to Protein When Exercising

Changing your body takes hard work.

Hard work with the weights, on the road, or logging cardio time, are all popular ways in which your efforts can translate into the results you want.

While some of what I will cover here will be very obvious to some of you more experienced athletes, its important for all athletes (beginner to professional ... and if you move your body with purpose for a workout and strive to get better ... you classify as an athlete) to understand the ramifications of lacking or non-existent post-workout nutrition.

This is an area that many people just do not understand the importance of and their progress definitely suffers from this lack of understanding.

Scientists have proven that consuming nutrients at key times can provide significant support to your exercising efforts, and nutrition after your workout is critically important to help your body recover and begin the road to a better you.

Whether you are someone that hits the weights and shutters at the thought of cardio or you are more about the cardio side of fitness who would rather do cardio as opposed to weights ... post-exercise nutrition remains an important consideration [1].

A number of substances are found within our body that provides fuel for these workouts and the most important is glycogen, a form of carbohydrate, found in our muscles.

During prolonged exercise bouts of moderate-intensity or more intense workout sessions of shorter duration, the amount of muscle glycogen burned goes up.

For example, studies have shown that during one bout of resistance-type exercise, muscle glycogen stores can be reduced by 30 – 40% [2] and as expected even more glycogen is burned when higher intensities are used [3].

For these reasons, the ingestion of carbohydrates after exercise is emphasized, but more recent work suggests that adding protein to carbohydrates may further promote glycogen recovery and can help reduce muscle damage, both important considerations for regularly exercising athletes [4, 5].

In addition, it has been suggested that carbohydrate ingestion can positively improve the balance of protein in the muscles (a good thing) by reducing the amount of muscle breakdown [6], but recent studies have shown carbohydrate’s role at preventing muscle breakdown is limited to when only carbohydrate is ingested [7].

If you aren’t sure of the negative impact of starting your next workout with less than adequate glycogen levels or think you can power through better than the next guy just fine, consider this.

When trained cyclists completed a pre-determined bout of cycling exercise with either high or low levels of glycogen, the greatest performance occurred when the exercise bout was started with higher levels of muscle glycogen, whether a sports drink was ingested during the exercise bout or not.

This is big-time information to consider because it clearly shows that if your recovery efforts are lacking, subsequent workout performance WILL BE negatively impacted [8]!

A final area to talk about the positive impact of carbohydrate ingestion during regular intense exercise relates to the positive impact it has on your immune system.

Nobody wants to get sick as it seems like nothing can derail your efforts faster than getting a cold or the flu.

Stressful exercise is known to stimulate sharp increases in stress hormones such as cortisol and additional studies have shown that exhaustive exercise can increase a number of key factors associated with inflammation and health of the immune system [9].

When some form of carbohydrate is ingested while completing a weight workout, improvements in the overall functioning of the immune system have been shown to result [9, 10].

Impressively, the power of carbohydrates to support the immune system goes up immensely as the duration of exercise goes up and the amount of rest is reduced as seen with bouts of cardio exercise [11, 12].

In summary, whether you are a cardio buff or like to sling steel during your workouts, the importance of carbohydrate surrounding your workouts (particularly after your workout) cannot be understated!

The positive effects are numerous and include providing an effective fuel source during the workout, helping to recover spent muscle glycogen, minimizing muscle soreness and muscle breakdown or supporting your immune system … all of these contribute to better performance … not to mention it also tastes good!

Simply put, science would tell you that if you want the best results, don’t skip post-workout nutrition.

REFERENCES

1. Kerksick, C., et al., International Society of Sports Nutrition position stand: nutrient timing. J Int Soc Sports Nutr, 2008. 5: p. 17.
2. Koopman, R., et al., Intramyocellular lipid and glycogen content are reduced following resistance exercise in untrained healthy males. European journal of applied physiology, 2006. 96(5): p. 525-34.
3. Robergs, R.A., et al., Muscle glycogenolysis during differing intensities of weight-resistance exercise. J Appl Physiol, 1991. 70(4): p. 1700-6.
4. van Loon, L.J., et al., Maximizing postexercise muscle glycogen synthesis: carbohydrate supplementation and the application of amino acid or protein hydrolysate mixtures. Am J Clin Nutr, 2000. 72(1): p. 106-11.
5. Zawadzki, K.M., B.B. Yaspelkis, 3rd, and J.L. Ivy, Carbohydrate-protein complex increases the rate of muscle glycogen storage after exercise. J Appl Physiol, 1992. 72(5): p. 1854-9.
6. Borsheim, E., et al., Effect of carbohydrate intake on net muscle protein synthesis during recovery from resistance exercise. J Appl Physiol, 2004. 96(2): p. 674-8.
7. Koopman, R., et al., Coingestion of carbohydrate with protein does not further augment postexercise muscle protein synthesis. Am J Physiol Endocrinol Metab, 2007. 293(3): p. E833-42.
8. Widrick, J.J., et al., Carbohydrate feedings and exercise performance: effect of initial muscle glycogen concentration. J Appl Physiol, 1993. 74(6): p. 2998-3005.
9. Carlson, L.A., et al., Carbohydrate supplementation and immune responses after acute exhaustive resistance exercise. International journal of sport nutrition and exercise metabolism, 2008. 18(3): p. 247-59.
10. Koch, A.J., et al., Minimal influence of carbohydrate ingestion on the immune response following acute resistance exercise. International journal of sport nutrition and exercise metabolism, 2001. 11(2): p. 149-61.
11. Nieman, D.C., et al., Muscle cytokine mRNA changes after 2.5 h of cycling: influence of carbohydrate. Med Sci Sports Exerc, 2005. 37(8): p. 1283-90.
12. Nieman, D.C., et al., Carbohydrate ingestion influences skeletal muscle cytokine mRNA and plasma cytokine levels after a 3-h run. J Appl Physiol, 2003. 94(5): p. 1917-25.