Pre-Workout Protein Intake: New Insights

A Deeper Look into Pre-Workout Nutrition
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It shouldn’t be news to anyone that you can, and perhaps should, take a protein drink before you work out. This was actually the basis upon which I sold my own brand of protein powders back when my dietary and sports supplement company, HSN, was still in business. The idea was based on research showing that if 
you could get your blood amino acid levels high before your workout, the increase in blood flow would enhance the delivery of those amino acids to the muscle tissue that you were working.(1) This enhanced delivery of amino acids boosted the anabolic effect. But then other research was done using various protein sources taken at various times surrounding a workout, and as you might expect, they produced various results, not all of them significantly better than any other. Some confusion and even debate has existed since then about just what type of protein is best to take and when, to maximize the anabolic effect of taking a protein drink.

This uncertainty about what 
to take and when led researchers working out of the Australian Institute of Sport to conduct an experiment that would shed light on whether a fast-digesting protein or a slow-digesting protein was better to take before training.(2) This is how they set it up; 12 resistance-trained subjects did a workout of single-leg extensions under three different experimental conditions. The leg extensions were performed on one leg during one workout while the resting leg would be trained during the subsequent workout and so on. The subjects were given one of three different drinks 
45 minutes prior to the workout: a placebo drink, 30 grams of whey plus 5 grams of leucine taken all at once, or 30 grams of whey plus 5 grams of leucine taken in 15 small doses (also called pulse feeding) to simulate a slow-digesting protein. Using the exact same protein source to simulate a slow-digesting protein eliminates questions about amino acid compositions affecting the results. Each experimental condition was separated by a one- to two-week washout period with no training.

Interestingly, the pulse-feeding protocol achieved higher amino acid and insulin concentrations after training than a single ingestion of the same protein. The elevated post-workout blood amino acids and insulin associated with pulse feeding resulted in enhanced activity of key anabolic signaling pathways (such as the Akt-mTOR-p70S6K pathway) at one hour post-exercise compared with drinking the protein all at once. To quote the authors, “Unlike the intake of proteins after resistance exercise, where a rapidly digested protein produces a superior muscle protein synthetic response, when it is consumed prior to the exercise session, there is no disadvantage to consuming a protein source that produces a slower AA [amino acid] response as long as the [serving] size is adjusted to achieve a high leucine.”(2) The overall increase in protein synthesis during five hours of recovery was not significantly different between the two protein protocols.

What this means is you don’t have to worry about getting the fastest-digesting whey protein on the market if you are going to take it before your workout. In fact, according to this study, it wouldn’t hurt to stretch it out a little and perhaps sip it throughout your workout.

 

References: 1) K.D. Tipton et al., Am J Physiol Endocrinol Metab., 281(2):E197–206, 2001. 2) L.M. Burke et al., Med Sci Sports Exerc., May 22, 2012.

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