protein intake

Becoming a Protein Intake Pro!

Part 3: Doing it the right WHEY!

By Mike Brennan – BSc (Hons) Sport & Exercise Sciences

protein intake

So far we have addressed two important aspects of protein intake: daily requirements and nutrient timing. We all know by now that if you lift weights or engage in strenuous exercise, protein is important. So much so that protein supplements have been developed to compliment this and are used by many.

Now I will state upfront that I DO NOT think that anyone NEEDS protein supplements if they are eating a balanced diet with sufficient amounts of protein from solid foods. However, I appreciate that mixing a protein shake is quicker than scrambling eggs or grilling a chicken breast. Therefore, protein supplements can be used out of CONVENIENCE BUT NOT NECESSITY.
With this in mind, we will now look at the common sources of protein found in protein supplements and compare and contrast their effectiveness.


Whey, Casein or Soy?

Whey, Casein or Soy protein are the three protein sources most commonly used in protein supplements. There are certain factors that may influence which protein source someone chooses such as food tolerance (e.g. lactose intolerance) or dietary practices (e.g. veganism/plant-based diets). Aside from these factors some people may struggle to differentiate between these three common sources of protein. Research has shown that some protein sources may be better than others.

A study compared whey, casein and soy protein and the degree to which they stimulate muscle protein synthesis when consumed post training. As discussed in part 1 and 2, muscle protein synthesis plays a key role in muscle growth.
This study found that whey protein was superior to casein and soy protein at increasing muscle protein synthesis (Tang et al., 2009). It was also suggested that this superior response may have been due to its high leucine content and possibly the fast digesting nature of whey protein.

Therefore, whey protein may be superior to casein and soy protein as it causes a greater stimulation in protein synthesis.

 protein intake

What is Leucine?

As mentioned above, the study suggested that the superiority of whey to casein and soy protein may be due to its high leucine content. Leucine is an essential amino acid (EAA) and is also categorised as one of the three branched-chain amino acids (BCAA).

Leucine has been shown to stimulate the mTOR signalling pathway which in turn stimulates muscle protein synthesis (Drummond & Rasmussen, 2008). It is reasonable to infer that the effectiveness of whey protein (and other leucine-rich protein sources) is largely due to its high leucine content.

Therefore, protein sources rich in leucine (such as whey) are preferable as they stimulate muscle protein synthesis greater than protein sources with a lower leucine content.


Doing it the right WHEY: Key Points

  • Whey protein is superior to casein and soy protein at maximally stimulating muscle protein synthesis.


  • Leucine-rich foods are superior at stimulating muscle protein synthesis due to the stimulation of the mTOR signalling pathway.


  • Protein powders are NOT A NECESSITY but may serve as a convenient source of protein.


  • An effort should be made to meet your protein requirements through the consumption of solid foods before considering protein supplementation.



Drummond, M.J. and Rasmussen, B.B., 2008. Leucine-enriched nutrients and the regulation of 371 mammalian target of rapamycin signalling and human skeletal muscle protein synthesis. Current 717 opinion in clinical nutrition and metabolic care, 11(222-226), p.718.


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