Post Workout Protein - Is 20g Of Protein Enough?

When it comes to getting protein in post-training, most people would agree that it is beneficial – whether it is for muscle growth or recovery. But how much is enough? For a long time, it was believed that you needed no more than ~20g of whey protein post-training. But why? And is this still the case?

Studies examining how much (and what type of) protein we should take post-training come from studies that use isotopes to measure how much ‘new’ protein we are able to make in our muscles after training – this is the whole point of training. Earlier studies showed that there was no added benefit for muscle growth beyond 20g of protein – even if you doubled the intake to 40g (1). This did spawn one myth that should be put to bed.

The myth that your body can’t handle any more than 20g of protein in one go needs to be put straight into the bin and never return.

If you consume more protein than this in one sitting, it is just used for other processes within the body. It might go to a vital organ, it can be used for energy production – it is not just wasted.

A New Protein Ceiling

This original work though showing that there is no added benefit for muscle growth beyond 20g stuck for a long time though. That was until two recent studies.

The first study again looked at 20g vs 40g. But, unlike the original study that used a leg only training session, this new study used a whole body resistance training session (2). Their theory was that, as we were using more muscle mass, we would most likely need more protein afterwards. What did they find? A 20% increase in skeletal muscle synthesis when participants took on 40g vs 20g.

So, it appears that how much protein you consume after training or competition might depend on how hard the session was and how much of the body was used. Full body session? You might need up to 40g of protein. Upper or lower body only, you maybe only need around 20g.

Training Into Old Age – More Of The Same?

A very recent study has even shown that 40g may be more beneficial post-training as we age. Unlike the study in younger adults that used tracers to measure protein synthesis after a single training study – this study in older adults wanted to look at the practical effects of consuming either 20g or 40g post training (3). Those in the group consuming 40g post-training showed significantly improved strength performance in chest, shoulder and leg press compared to a matched group that only consumed 20g. Same training – but better results. 

Something to think about as we age.

References

1 – Shing, C. M., Peake, J. M., Lim, C. L., Briskey, D., Walsh, N. P., Fortes, M. B., … & Vitetta, L. (2014). Effects of probiotics supplementation on gastrointestinal permeability, inflammation and exercise performance in the heat. European journal of applied physiology, 114(1), 93-103. 

 2 – Roberts, J. D., Suckling, C. A., Peedle, G. Y., Murphy, J. A., Dawkins, T. G., & Roberts, M. G. (2016). An exploratory investigation of endotoxin levels in novice long distance triathletes, and the effects of a multi-strain probiotic/prebiotic, antioxidant intervention. Nutrients, 8(11), 733.

3 – Suckling, C., Roberts, J., Peedle, G., Gordon, D., Marshall, H., Taylor, L., & Roberts, M. G. (2016). Probiotic Supplementation and Gastrointestinal Endotoxemia Before and After the Marathon Des Sables. Medicine & Science in Sports & Exercise, 48(5S), 249-250.

4 – Pugh, J. N., Sparks, A. S., Doran, D. A., Fleming, S. C., Langan-Evans, C., Kirk, B., … & Close, G. L. (2019). Four weeks of probiotic supplementation reduces GI symptoms during a marathon race. European journal of applied physiology, 119(7), 1491-1501.