The scary truth about soy protein and bodybuilding

Inevitably, there is a myth that soy protein is horrible for bodybuilding and that if you are serious about working out or building muscle, you will stay away. In fact, some sites show ‘studies’ that soy protein and soy products can be harmful to health. And while it’s true that the early claims about the wonders of soy might not be entirely true, there’s also the myth that soy protein is bad for you.

First of all, there is a concept called the Biological Value Scale that was developed to measure the quality of specific proteins. Basically, it rates how efficiently your body will use a given protein source. The higher the BV (biological value), the more amino acids and nitrogen your body retains from the food you eat. In short, it becomes a way of measuring potential for quality muscle growth and strength.

There was a time when egg whites were at the top of the BV scoring around 100. Since then, whey proteins have topped the scale around 106-159 BV. This means that whey protein is best used for quality muscle growth.

But first a warning!

This does not mean that all you would use is whey protein for all your needs. Often times, bodybuilders will use a variety of proteins depending on BV and times of day and whether they just finished a workout.

Let me explain… Your protein needs in the morning are different than they are in the middle of the day and are different again AFTER a workout and different again before bed.

All of this means that no one protein is the best at any given time. But before I get lost… let me show you the biological value scale in a simple way.

Protein Type :: Biological Value Classification

Whey: 106-159 Egg: 100 Cow’s milk: 91 Fish: 83 Casein: 80 Beef: 80 Chicken: 79 Soy: 74 Wheat gluten: 54 Beans: 49

For all these reasons, you can and should see soy protein listed below. That just means it’s not the most anabolic protein for optimal muscle growth.

But don’t get me wrong…

This doesn’t mean you shouldn’t eat soy protein if you enjoy it. It simply means that barring religious beliefs or personal preferences, soy would not be the ideal protein source to increase muscle gains. This does not mean that you cannot have it or that it is bad for you.

In fact, let’s continue with a small example.

John Q. Public 13% Body Fat 184 lbs. 160 lbs. LBM (Lean Body Mass)

For simplicity, we’ll just say that for every LB of LBM (pound of lean body mass) John wants to get 1g of protein.

John should consume 160 g of protein per day.

This is where the myth and some problems come into play! Please read carefully.

If you get a lot of your protein from less than optimal BV sources (beans, soy), you won’t prime your muscles for optimal anabolic growth. John should not consume more than 150 grams of soy protein per day IF he wants to build the most muscle mass and has no personal reasons not to use better quality sources.

John also won’t risk losing muscle or wasting his efforts by eating small amounts of soy protein because he likes it. Having soy in his cereal won’t make a difference.

The myth that soy will cause men to produce estrogen is when LARGE amounts are ingested. Far beyond what any rational person would want to do in the long run.

A bodybuilder who has soy will not feel any difference, he will be less anabolic than someone who does not consume soy at all.

Fact: A long-term metabolic balance study in young men was published to assess the nutritional quality of a soy protein isolate and beef proteins (VR Young, A Wayler, C Garza, FH Steinke, E Murray, WM Rand and NS Scrimshaw) in 1984 by the American Journal of Clinical Nutrition. Am. J. Clinical Nutrition, January 1984; 39:8-15.

After 84 days from two groups, one totally isolated from soy protein and the other from beef protein, it was concluded that:

“Body cell mass measurements did not reveal any deterioration in protein nutritional status. These observations confirm the prediction, derived from previous short-term nitrogen balance studies, that the nutritional quality of soy protein isolate is high and that this vegetable protein may serve as the sole source of essential amino acids and nitrogen for protein maintenance in adults.”

So let me summarize and review…

Soy is not the most biologically available source for optimal anabolic muscle growth. If you were to finish a workout, you’d like to have some high-quality whey protein vs. soy proteins. However, just having soy doesn’t mean it’s bad for bodybuilding, unless you get most of your protein from soy products. So it’s not optimal. You would also need to be ingesting quite a bit on a daily basis for the negative effects of soy to kick in (specifically targeting men in this sentence).

Copyright 2006 Marc David