If youโre at all serious about gaining muscle and looking your best,ย protein is the name of the game.
This macronutrient provides the building block of our muscles and ligaments, making it an essential part of dietsโespecially for those who hit the gym regularly.
And as we all know, thereโs nothing like a steak or a chicken breast to give our body its fill of muscle juice. Getting enough dietary protein throughout the day is absolutely critical for optimizing lean body mass with weight loss and resistance training.
Whether itโs pre- or post-workout, whey protein supplementation is unparalleled. This is also why whey protein powder is the closest supplement to being considered โnecessary.โ
However, animal-based proteins arenโt the end-all and be-all of protein.
Although animal sources of protein are largely considered to be high-quality, โcompleteโ proteins, thereโs a whole world of plant-based proteins that offer unique benefits. The largest issue is that none of these are considered entirely complete. Wellโexcept for soy protein.ย
So, how does it measure up to the golden standard set by whey?
What differentiates soy protein from other plant-based proteins is its โcompleteness.โ But what exactly is a complete protein?ย
There are over 20 different amino acids that act as the building blocks for thousands of different types of proteins that are found just in our bodies.
Although most of these amino acids can be produced by our bodies, nine of these cannot.
For a protein to be considered complete, it not only has to contain all nine of the EAAs, but it also has to have them in sufficient ratios. For example, pea protein is low in methionine, which prevents it from being considered complete.ย
Amino acids can be further subdivided into branched-chain amino acids (BCAAs) which are primarily used in the muscles. Theyโre therefore believed to play a particularly important role in muscle development.
Whey protein powder comes from cowโs milk, as a by-product of the cheese-making process. That watery liquid that sits on top of yogurt when you open a container is whey.ย The protein powder itself goes through different levels of processing to create the substance that we all know and love.
Because whey protein is an animal product, it offers a complete amino acid profile.
Not only are there high levels of all the amino acids, but the protein is also extremely bioavailable, allowing it to be quickly absorbed by our bodies.ย These factors make whey protein powder the golden standard of protein supplementation.
Itโs a relatively cheap and plentiful source of protein thatโs accessible and easily implemented within diets and workout routines.
However, whey protein obviously doesnโt work with a lot of different dietary restrictions. Even looking past vegan diets, some people also have lactose intolerance.
Whey protein can sometimes not agree with peoplesโ digestive systems, leading to gassiness, bloating, discomfort, and other stomach issues.ย
Due to these reasons, plant-based alternatives have been seeing increasing popularity. Chief among these is soy protein powderโbut is it a worthy alternative?
Soy protein powder comes from the legume called soybean. Soy milk, tempeh, edamame, and tofu are all directly made from soybean.
Having been eaten by humans for over 5,000 years now, it is one of the only plant-derived proteins that is considered a complete protein.ย
Other than the protein itself which makes up roughly a third of soy, another 30% is carbs, 19% is oil, and 14% is water (moisture). Itโs especially unique in that itโs very fatty, and therefore it finds uses in a surprising amount of foods.
However, soy is also found in a ton of different baked goods, candies, and soap. Itโs even sometimes found in whey protein powder because it contains an emulsifier that makes the whey easier to mix.ย
This plant protein also contains a significant amount of zinc, potassium, iron, phosphorus, vitamin E, and vitamin B complex.
It can also help to keep cholesterol under control in those whose cholesterol is within normal levels.
On paper, this sounds great. However, there is a reason why soy has attracted so much scandal over the years.ย This can be generally encompassed by looking at soyโs effects on muscle building, on estrogen and testosterone, and its antinutrients.
The big question that it comes down to, is whether soy is comparable to whey when it comes to the benefits it has on our training and body composition. Whey has been consistently shown to increase muscle size and training capacity when used with a training regime.
There are two factors that opponents of soy bring up:ย
The first argument is that although soy contains all nine EAAs in sufficient quantities, it contains much less leucine which is important for muscle protein synthesis (the process that builds our muscles to be larger and stronger).ย
The second argument is that soy contains phytoestrogens which โfeminizeโ men by increasing estrogen levels and decreasing testosterone levels. While the scientific evidence argues against this, it is worth looking at the studies that have shown otherwise. But first, letโs compare soy and whey when it comes to building muscle mass.
Both soy and whey share all nine of the essential amino acids, so that means they should be equally as good at eliciting gainsโright?ย
Well, we donโt conclusively know. But there is good evidence that suggests soy might be slightly less optimal because it contains less of the EAA, leucine.
Leucine is believed to be the most important amino acid in muscle protein synthesis (MPS). Muscle protein synthesis is a critical process that tells our muscles when to develop and grow, so it follows that itโs critical for optimizing our gains. This isnโt to say that all you need is leucineโitโs only one part of a myriad of compounds that help your muscles grow. However, it still holds a special place.
Whey protein, when compared to many other proteins, has a very high amount of leucine. Because of this, the absorption rate of the protein content is much higher. For every 100 grams of whey protein isolate, there should be between 11 and 13 grams of leucine. The same amount of soy protein isolate will net you 8 to 9 grams of leucine.
When converting down to scoops, whey will have about 3 grams of leucine while soy will have just over two.
This difference is small and it only really matters if youโre concerned primarily with muscle protein synthesis. Which, to be fair, is an important concern if youโre trying to eke out every improvement you can in your training.
Itโs an even more important concern when you consider that leucine has a threshold it has to reach before triggering muscle protein synthesis. Although studies in this area are pretty inconclusive, itโs believed that this threshold is 3 grams.
But here's the deal, when leucine content is controlled between whey and soy protein, there isย ย no significant difference in muscle growth and strength development.ย
For example, eating 30 grams of either protein will likely mean that thereโs no difference between the two in muscle protein synthesis. What this means is that you need to take slightly more soy protein to match the leucine content of whey.
And this tentative โconclusionโ only deals with one aspect of growing bigger and stronger (albeit an important one)โmuscle protein synthesis.ย Whether you believe this is a big deal or not is going to largely come down to the individual, and itโs also part of the reason why soy has seen so much debate around it.
The next biggest part of the debate is whether soybeans feminize men by messing with levels of estrogen and testosterone.ย The argument is that the phytoestrogens in soy (namely, isoflavones) act like estrogen in the human body.
Before we continue, it should be mentioned that many different foods contain phytoestrogens, including apples, carrots, rice, and coffee. Furthermore, there have also been a lot of health benefits linked to phytoestrogens.
But the question still remainsโdoes soy mess with our sex hormones? As with most good debates, thereโs evidence on both sides of the argument.
However, thereโs definitely more evidence that shows that soy doesnโt have any effect on testosterone levels in males.
And the studies that do suggest that soy messes with hormonal balances also have subjects consuming a ton of soyโeven up to 3 liters of soy milk daily. The truth is that the phytoestrogens in soy are very likely not going to make any detrimental difference in your training or your physique.
Even if there were definitely negative effects, these effects would be so small that dozens of other factors would come into play before. Your routine and diet would have to be seriously tuned in for phytoestrogens to be the deciding factor in your success.ย However, itโs still good to stray on the side of caution.
While soy is likely not going to have any detrimental effects, itโs also a good idea to be aware of them and change your routine accordingly.
For both the question of gains and the question of testosterone, age was one of the biggest factors that most studies saw a difference in.ย
Older people are going to need more leucine to get past the muscle protein synthesis threshold, so either eating more soy protein or supplementing with whey can be a good idea in this scenario.
Older people also seemed to be more affected by phytoestrogen, albeit, when soy intake is extremely high.ย If youโre young, then thereโs an even better chance that these factors donโt matter as much.
Having addressed the biggest points of contention when it comes to soy protein as compared to whey, we can address some of the other questions that make up another large part of the discussion.ย
The biggest factor is the unique nutrient profile of soy. As weโve seen already, it has both its alleged benefits and alleged drawbacks. However, thereโs more to be said about anti-nutrients and isoflavones.ย
Lastly, practical things like diet and taste should also be taken into consideration when trying to decide between soy protein powder and whey.
Aside from the factors weโve already looked at, there are three more main aspects that separate soy protein from whey.ย
While there is no conclusive evidence yet, there have been studies that have shown how soy raises the output of the thyroid. What does this mean practically speaking?
It means that it could make it easier to shed some fatโsomething thatโd be particularly useful for bodybuilders.
Although complete proteins overall have been shown to raise levels of thyroid hormone, it seems that soy has a unique effect that elevates it from other proteins.ย
There has also been evidence that shows that the isoflavone in soy (which is a phytoestrogen) is beneficial for the human body. This is because isoflavones have an antioxidant effect on us, meaning that thereโs less inflammation, for one. When it comes to working out, this is especially important because it shows that soy can potentially help speed up recovery while reducing soreness.
Along with the questions around soyโs usefulness as a muscle-building agent and its effects on estrogen, another large question has been around the antinutrients found in soy. Antinutrients are compounds that actually block some of the absorption of different types of nutrients.
Lectin is the antinutrient thatโs often cited when it comes to soy, but another one is protease inhibitors. This might sound like a nail in the coffin for soy, but things arenโt as dire as they seem.
Even ignoring the fact that humans have been eating soy for a very, very long time with seemingly no repercussion, the modern manufacturing process of soy protein takes into account a lot of these drawbacks.ย For example, high-quality soy protein often has its antinutrients either completely or mostly removed. This allows it to have all of the benefits without any of the drawbacks.
The manufacturing process even addresses soyโs relatively low biological value (the availability of nutrients for our bodies). What hurts soyโs low biological value is its relatively low level of methionine, but many companies add this amino acid into the powder to increase its bioavailability.
Outside of the question of nutrients are also the dietary considerations that will persuade people for one or the other.ย
If youโre vegan, soy protein powder can be an obvious choice if youโre looking for a plant-based protein powder with a full amino acid profile.
But vegans arenโt the only ones who might want to consider switching over to soy.ย Whey protein powder can be hard on some peopleโs digestive systems. It can lead to gassiness, bloating, and cramps.
A plant-based powder like soy can help a lot of people in this aspect, even if they might not necessarily be lactose intolerant.ย And even ignoring the environmental considerations between plant and animal-based proteins, thereโs also the simple fact that variety is good for your gut.
You want to get your protein from different sourcesโpeople werenโt made to stick to one source of a nutrient for their entire life.
While this may be the least important aspect when it comes to the grand nutritional debate, itโs still important as a practical factor. Why does any of this matter if you find one or the other absolutely disgusting?ย
In this regard, whey gets most of the points.
Thereโs a reason that whey is so accessible and easy to implement into any lifestyle. It has a relatively neutral taste and when mixed with water or milk, it has a creamy texture.
Although different manufacturers will produce slightly different textures, this is largely true for most of them.ย On the other hand, soy protein has a grainer texture that might take some getting used to. It also has a stronger, nuttier flavor than whey protein.
This will come down entirely to personal preference, but there are always a ton of flavors to experiment with for both whey protein and soy.
Whey has been the golden standard of protein supplementation for decadesโand for good reasons. It provides a high-quality protein thatโs extremely bioavailable and easily absorbed by the body. Itโs very likely that nothing will ever topple it from the top. However, there will be increased interest in substitutes.
As we all know by now, itโs seen its fair share of infamy as both an ingredient to be avoided, and as a substitute thatโs actually better for us. And as with most things in the health world, conclusive statements canโt be reached.
Nevertheless, most of the evidence we have seen points to it being another, healthy source of protein.
But at the end of the day, supplements should be an afterthought to a well-rounded and varied diet. Even if the highest quality protein powder with a ton of purported benefits isnโt going to (and shouldnโt) measure up to a balanced meal that includes a variety of nutrients.
Humans need variety, and leaning on one source of protein (or any other macronutrient) isnโt going to cut it.ย Experiment, try new things, and make mistakes, because variety is the spice of life and thatโs the only way weโll learn new things.
If you're looking to try something new and delicious, check out all of our best-selling proteins to see which ones you like best!
