Pros and Cons of Soy Protein

Pros and Cons of Soy Protein

Over the past few years, we have become more aware of how things we eat are obtained. Some of us have an issue with how our dairy products are processed regarding animal welfare. Or perhaps some of us are just Lactose Intolerant and we are forced to look for different options than Whey Protein.

Whatever the reason, soy protein is an excellent option, regardless which group you belong to. It contains all the Essential Amino Acids (components that our body needs in order to function but cannot synthesize them = we have to get them from food). It basically has all the benefits of Whey, just without upset stomach (for lactose intolerant).


It however contains components called Isoflavones that are structurally similar to Oestrogen which is a female sex hormone. Some men believe that soy protein can affect the hormones and skew their testosterone levels. It has not been clinically proven. In Asian diet, soy is an important food and it appears in many varieties (miso, tofu, tempeh,…) As far as the studies go, Isoflavones are similar to Oestrogen only because of their structure, not function. I have known quite a few men over the years that chose soy protein as their main source and I have to say I haven’t noticed any moobs 🙂


If you want to avoid Whey because of sustainability issue, I would look into how the particular soy used in your chosen protein brand is sourced. As with everything, just because it is plant based, it doesn’t necessarily mean it’s sustainable. Rainforests are cut down not to just make space for grazing cattle, but also for plantations. The Biggest issue right now being Palm Oil issue, soy coming close behind. It can also be genetically modified (GMO) but that is the case for almost every vegetable so I wouldn’t necessarily shame just soy.


What is, in my opinion, excellent about Soy Protein is that it is naturally very low in fat (especially saturated fat which is the worst type for our body) and cholesterol which means very good news for people trying to lose weight and still add some extra protein to their diet.

It also contains high levels of Iron which is very important information for women and athletes in general. Studies suggest that most women are low in Iron without even realizing it. It is a very important micronutrient because it’s the component in our red blood cells that carries oxygen around. If we are low or even deficient in Iron, our body cannot deliver Oxygen to tissues efficiently and performance decreases.  Non-heme Iron (plant source), however, is not absorbed as well as Heme Iron (animal source). There is a quick and easy fix for this, though. Vitamin C significantly aids Iron absorption and It is a Vitamin that is very difficult to get deficient in.


The only issue I sometimes had with some Soy Proteins is structure, taste and the fact that they quite often don’t mix very well. They are fine in a blender but If you just need a quick shake after gym, It might not be the best choice. However, a lot of brands is addressing this issue and they add components to the powder so it mixes better. But that only means you have additives in your protein shake and I am not a great fan of them. They are in every single food we buy and to add more just because my shake is just a bit grainy seems unnecessary to me. You can always mix them in a blender or throw a banana in there if you want to make a smoothie:) They are offered in a great variety of flavours, too.


Soy Protein is a very good quality protein, however Whey supports protein synthesis in muscles (muscle growth) a bit better. Animal protein is digested and absorbed  easily than plant based. (Yes, we have all seen the “Gamechangers” and “What the Health” documentaries about meat and they are right in one thing – meat is very processed these days and farms where animals are kept are far from a comfortable environment, but maybe we can cover it in a different article. For our purpose now It is more than correct to say that human body processes animal protein quicker – egg (albumin) being the best one that all other proteins are compared to). This could be of importance I you are really serious about muscle building.

Better muscle protein synthesis in Whey is also due to a component called Leucine which is an Amino Acid that plays a very important role in muscle growth.  It is best to have 2g – 3g of Leucine (2.5g seems to be ideal) in your protein shake to trigger the effect. General rule of thumb is that every 30g of Whey Protein Powder contains the 2.5g that we need but always read your label. Soy Protein Powder just about hits the mark of 2g which is the minimum you need to start the effect so, from a bodybuilding point of view, there is no surprise that whey is preferred.

One scoop of soy, compared to one scoop of Whey, is also generally lower in protein content. But if you are not a body builder trying to eat 50g of protein in every meal, this shouldn’t be an issue.


Yes, there are controversial issues around Soy in general but I’d say, If you do your research regarding GMO and sustainability and you are a Vegan, Soy is perfect for you. It contains a lot of important nutrients like Iron, Zinc, Phosphorus etc. And the Oestrogen issue? Well, I think that if you have a balanced diet you have nothing to worry about. As the very old saying claims: “Everything in moderation”

Listen to your body.

Does your body take Soy Protein well?

Do you get upset stomach after consuming Whey Protein?

Do you like the taste and structure?

Give it a try and let me know.

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