Chocolate Milk for post workout recovery

Recently Chocolate milk has been receiving quite a bit of attention as a post workout recovery drink for athletes.  At initial glance this would appear to be a bit of a shocker as levels of lactose intolerance are high and common as well as the protein composition of milk.  Before we look at the research, let’s look at the nutritional composition of chocolate milk.  With a serving size of 250ml giving us 160 kcal, 2.5g of fat, 180 mg of Sodium, 27 g of carbohydrates and 7 grams of sugar.  Milk contains two types of proteins; whey and casein in a 2:8 ratio respectively.   Whey is a rapid digesting protein that has an amino acid profile that stimulates lean mass production, whereas Casein is a slow digesting protein that curdles in the stomach and slows down digestion in general (Tang et al. 2009).  Upon this initial inspection, one would question why chocolate milk is being promoted as a recovery beverage, but a closer inspection of the research shows something very different. 

In 2011, Lunn and colleagues looked at the effect of acute endurance exercise’s effects on protein catabolism (muscle breakdown) and the interaction and influence of whole-food protein and carbohydrate sources such as fat-free chocolate milk.  Researchers looked at fat-free chocolate milk consumption in male runners after a 45 minute run.  Protein turnover was determined with muscle biopsies and infusions of phenyanaline and leucine.  When compared to subjects that were given a protein-free carbohydrate beverage after the run, the chocolate milk consuming group had higher skeletal muscle protein synthesis and reduced rates of catabolism.  The reason for this is because adequate glycogen replenishment will assist in exercise performance as well as post-exercise protein turnover.  Additionally, because of the greater carbohydrate content of chocolate milk, this assisted in the recovery for these runners. 

Another study by Thomas and colleagues (2009) looked at chocolate milk consumption amongst trained male cyclists.  Serving as their own control group, the cyclists cycled for 43% longer after ingesting a carbohydrate replacement drink or a fluid replacement drink.  Pritchett and colleagues (2011) also looked at chocolate milk’s influence on male cyclists.  They gave the cyclists low-fat chocolate milk as a recovery beverage daily for an entire week.  The study did not find a significant difference between the chocolate milk and recovery beverage.  They speculate that the reason for this is due to the different types of carbohydrates present in chocolate milk.  Chocolate milk contains glucose, fructose and lactose whereas the recovery beverages contain glucose, fructose and maltodextrin.  The researchers also go on to state that chocolate milk has an ideal Carbohydrate to Protein ratio of 4:1, which is similar to other recovery beverages. 

In terms of dosage, Cockburn and colleagues (2012) experimented with different volumes of chocolate milk given to athletes after exercise.   The anthropometric testing and blood samples were taken from healthy male athletes in both individual and team sports.  The study found that only 500ml of chocolate milk was sufficient to protect against exercise-induced muscle soreness.  

There is one thing in common with all these studies which is they look at endurance athletes.  In fact my literature search didn’t show much information on body builders or direct muscle synthesis with whole milk.  There are multiple research papers looking at Whey protein and Casein protein separately, but not many good quality research papers that look at the combined whole-food effect that milk or chocolate milk has.  With this gap in research no conclusions can be made about milk’s impact on pure muscle synthesis for bodybuilders, or for those not engaged in endurance based sports.  But for those of you that engage in endurance based sports such as running, long distance cycling, swimming etc. Chocolate milk may be the recovery drink for you. It has the ideal carbohydrate to protein ratio to replenish glycogen stores, lessens protein catabolism and is cheap, readily available and pre-made, making it easy to adapt into any regimen.  However, if you have lactose intolerance, IBS or any condition that makes tolerating milk difficult it would be worth while looking to other sources for a recovery drink.   But for those of you that can tolerate chocolate milk, it’s definitely an option to consider. 

References

Cockburn, E., Robson-Ansley, P., Hayes, P. R., & Stevenson, E. (2012). Effect of volume of milk consumed on the attenuation of exercise-induced muscle damage. European Journal of Applied Physiology, 112, 3187-3194.

Lunn, W. R., Pasiakos, S. M., Colletto, M. R., Karfonta, K. E., Carbone, J. W., Anderson, J. M., et al. (2011). Chocolate Milk and Endurance Exercise Recovery: Protein Balance, Glycogen, and Performance. Medicine & Science in Sports and Exercise, 44 (4).

Pritchett, K. L., Pritchett, R. C., Green, J. M., Katica, C., Combs, B., Eldridge, M., et al. (2011, December). Comparisons of Post-Exercise Chocolate Milk and a Commercial Recovery Beverage following Cycling Training on Recovery and Performance. Journal of Exercise Phyisology , 29-39.

Thomas, K., Morris, P., & Stevenson, E. (2009). Improved endurance capacity following chocolate milk consumption compared with 2 commercially available sport drinks. Applied Physiology, Nutrition and Metabolism, 34 (1), 78.

Tang, J.E., Moore. D.R., Kujbida. G. W., Tarnopolsky. M. A., Phillips. S.M., (2009). Ingestion of whey hydrolysate, casein or soy protein isolate: effect on mixed muscle protein synthesis at rest and following resistance exercise in young men. Journal of Applied Physiology. 107 (3) 987-992