Whey protein vs. Soy protein

Protein: Whey vs. Soy

One of the most frequent questions I get asked is:  What kind of protein is superior, whey or soy? In order to answer that question you must first have an understanding of the differences between them and how they work in the body.

Whey is obtained as a byproduct during the process of making cheese or can be separated from the casein in milk.  It is considered to be a high quality protein because it is a complete protein and contains all 9 essential amino acids. Soy protein is a plant based protein obtained from the soy bean.  It is also contains the essential amino acids.

When supplementing protein in the diet as part of a strength building or weight loss program the benefits of whey are preferable to soy.  Whey protein has a high bioavailability rate which means the body can use a high percentage of the protein making it beneficial for both the recovery and rebuilding of muscles.  This is significant for people looking to lose weight due to the fact that an increase in muscle mass will help speed up the metabolism. It is also the best source of leucine, isoleucine, and valine (essential amino acids) which are taken from the muscle during exercise.  Soy protein can also help the body form new muscle but has a much lower bioavailability rate making it less helpful in rebuilding muscle. It is also contains enzyme inhibitors which make it difficult to digest creating an increase in gas and bloating and has been known to obstruct digestion.  Overall, whey protein has a much higher absorbability rate (100-159) compared to soy protein (60) making whey protein a better choice for supplementing protein in a weight training or weight loss program.  For more information about nutrition, weight training, or if you’ve been thinking about hiring a personal trainer, contact us.