A common myth in the fitness industry is that a protein shake (and possibly including high GI CHO) must be consumed immediately after a workout to ensure maximum anabolic response and to prevent catabolism. What is often forgotten is that unless training in a fasted state, there will still be nutrients (amino acids, glucose and fatty acids) being absorbed from previous meals. If a person is training fasted then they may want to consume some protein post workout to inhibit muscle protein breakdown and activate muscle protein synthesis.
A study by Burd et al. came to the conclusion that amino acid sensitivity of myofibrillar protein synthesis was enhanced for up to 24 hours after resistance training in young men. Potentially, this means that as long as there is amino acids available muscle protein synthesis last a LOT longer than the typical 30-60mins that people often cite as the anabolic window.
To find the optimal level of protein intake at a meal we must determine what the optimal level of protein at a meal for stimulating muscle protein synthesis is. It appears that maximizing skeletal muscle protein synthesis requires approximately ~15g of an essential amino acids[1,2]. It has been postulated that the amino acid leucine is responsible for the stimulatory effect of dietary protein on protein synthesis and 15g of essential amino acids would contain 3.2g of leucine. This could be from a branched chain amino acid product or whey protein (as this contains the BCAA’s). Alternatively, a whole food meal could also be consumed.
Several studies have shown that the duration of protein synthesis in response to an oral leucine dose or an essential amino acid infusion is approximately two hours long[3,4] Even when oral leucine was administered for 6 hours the protein synthesis only lasted 2 hours. For this reason, it “may” be beneficial to consume a larger whole meal with more than the typical 30g of protein.
If a training session lasts 60 minutes or less and pre-workout protein containing meal (or drink) within half an hour of training or a full sized meal was consumed within 90 minutes (give or take) additional protein during training are unlikely to have any additional benefits. Amino acids and blood glucose levels will still be elevated from the pre-workout meal.
- Total macronutrients consumed daily is far more important than the timing.
- Nutrients will still be absorbed from meals eaten during the day (and yesterday if training early).
- The goal of post exercise nutrition is to rehydrate, provide amino acids to halt muscle protein breakdown (can also use carbohydrates) and facilitate muscle protein synthesis.
1. Paddon-Jones D, Sheffield-Moore M, Zhang XJ, Volpi E, Wolf SE, Aarsland A, Ferrando AA, Wolfe RR. Amino acid ingestion improves muscle protein synthesis in the young and elderly.
Am J Physiol Endocrinol Metab. 2004 Mar;286(3):E321-8.
2. Tipton KD, Ferrando AA, Phillips SM, Doyle D Jr, Wolfe RR. Postexercise net protein synthesis in human muscle from orally administered amino acids. Am J Physiol. 1999 Apr;276(4 Pt 1):E628-34.
3. Anthony JC, Lang CH, Crozier SJ, Anthony TG, MacLean DA, Kimball SR, Jefferson LS. Contribution of insulin to the translational control of protein synthesis in skeletal muscle by leucine.
Am J Physiol Endocrinol Metab. 2002 May;282(5):E1092-101.
4. Bohe J, Low JF, Wolfe RR, Rennie MJ. Latency and duration of stimulation of human muscle protein synthesis during continuous infusion of amino acids. J Physiol. 2001 Apr 15;532(Pt 2):575-9.
5. Burd NA, West DW, Moore DR, Atherton PJ, Staples AW, Prior T, Tang JE, Rennie MJ, Baker SK, Phillips SM. Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men.J Nutr. 2011 Apr 1;141(4):568-73. doi: