Protein for Athletes

Skeletal muscle holds nearly 60% of the total body protein in humans. Increased protein breakdown and decreased protein synthesis is commonly seen during strenuous activity and exercise, while protein building occurs during the recovery period.   However, the rate of protein turnover is dependent upon the type of exercise performed.  For example, endurance exercise, defined by training 10 hours or more per week, induces different levels of protein degradation as opposed to resistance/strength training exercise.   Athletes want to be in positive protein (nitrogen) balance and this state has been reached at a protein intake of at least 1.2 g/kg per day bases on clinical experiments in various types of athletes. ¹

As suggested in several publications, consumption of 15-20 grams protein (from skimmed milk or whey proteins) and carbohydrate (± 30 grams) is needed immediately after exercise (within 1 hour) to fuel muscle protein and tendon collagen turnover.^2,3

What type of Protein to consume?

Why choose whey protein over other types of protein?  Whey protein is more rapidly absorbed by the intestinal tract when compared to casein or whole milk.  Additionally, whey protein has been shown to have greater muscle protein synthesis vs. casein or soy protein³, most likely due to the high amounts of branched chain amino acids (leucine, isoleucine, and valine) found in whey.

Whey protein isolate has a very low lactose content (<1%) and higher protein concentration (90%) compared to whey protein or concentrate.  Therefore, whey protein isolate may be better tolerated in some individuals with trouble digesting lactose and milk.

References:

1. Lemon, PW. Beyond the zone: protein needs of active individuals [In Process Citation]. J Am Coll Nutr 2000;19:513S-521S.
2. Witard OC, et al. Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise. Am J Clin Nutr. 2014
3. J.R. Poortmans, et al. Protein turnover, amino acid requirements and recommendations for athletes and active populations. Braz J Med Biol Res, October 2012, Volume 45(10) 875-890

Disclaimer: This information is for informational purposes only and is not intended to replace or modify the advice provided by your doctor or other health care professional. You should consult a health care professional for all health-related matters, including before beginning any diet or fitness program and determining nutritional requirements.