Let’s start this article with a big spoiler…
No, soy protein isn’t much good for bodybuilders at all.
With that out of the way, let’s break down exactly why you shouldn’t waste your money on this less efficient form of protein powder.
What is Soy?
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Soy protein is a protein powder that works in principle just like whey protein. The big difference though is that soy is made from soy beans, whereas whey is made from whey (which is extracted from milk). This makes soy protein popular with vegans because they can consume it without breaking their diet.
But the problem with soy is that it really isn’t very good. Recent research is suggesting that perhaps it does have some merits under particular circumstances (which certain crowds are running with) but overall it’s by far the inferior product.
The Problem With Soy
Soy has many problems. To start with, soy protein is less biologically available which means your body can use less of it. Whey has a ‘BV’ value of 104, whereas soy’s is only 74. This means that you can eat the same amount of soy as whey but your body will be able to ‘use’ more of the whey.
To understand why this discrepancy exists, we should look at the difference between the two types of protein. On the one hand, whey comes from an animal source, which means that it’s designed for animals. The amino acid profile thus contains more IAAS (indispensable amino acids) versus DAAs (dispensable amino acids).
Essentially when you eat any type of protein, it is going to be recycled in your body into muscle and other tissue. Eating animal proteins makes more sense for the body because the state it’s in is already more similar to that of our own amino acids.
And it gets worse. You see, soy is also full of what are called ‘anti-nutrients’. These are pretty much like they sound: substances that have undesirable effects on the body such as blocking the absorption of the nutrients we do want into the body.
And soy is rich in estrogenic compounds like genistein and diadzein. These raise estrogen and lower testosterone ultimately resulting in less lean muscle mass, less drive and less libido. Oh dear.
In Defense of Soy
Of course, there are two sides of every argument. Some people will tell you for instance that soy companies are now able to remove the anti-nutrients, which is likely true to an extent. At the same time, soy does seem to have the benefit of raising thyroid hormones which may make it useful for fat burning.
But the effects on T3, T4 and TSH are minimal and shown only in controlled laboratory experiments. In other words, it’s unlikely to have a notable effect on your weight loss – you’re much better off with a conventional fat burner.
The moral of the story? People will spin any story to support what they want to believe. But we’re not bashing vegetarians here: just stating the facts. Soy protein isn’t as good as whey protein and it may even be detrimental to your gains. It’s that simple. Why do you think professional athletes and bodybuilders choose whey over soy? It’s not for giggles!