In the video posted above you can see Dr. John McDougall describe the dangers of soy protein isolate. Soy protein isolate is usually the main ingredient found in fake meats. I really enjoyed having Yves burgers for breakfast before coming to learn the possible adverse effects of consuming soy protein.

Will I ever eat soy based meats again? I probably will on special occasions, but for now, I’ll stick with vegan lentil burgers.

How are soy based “fake meats” made?

Soy protein is globular while actual meat protein is fibrous, so food manufacturers have to alter the soy’s molecular structure.

This is typically done by exposing the soy protein to heat, acid or a solvent and then running the mixture through a food extruder that reshapes it.

“When you denature the molecules, they open up and become more fibrous,” Barry Swanson, a food science professor at Washington State University. “Then you hold them together with a gel, such as carrageenan or xanthan gum, something that will hold a little bit of water, and what you get is something that vaguely resembles a piece of meat.”


Here is what Dr. John McDougall had to say about soy:

Fake MeatsSoy-food consuming populations of people, like the Chinese and Japanese, have a much lower incidence of heart disease, osteoporosis, and cancer of the breast and prostate. From this observation, many researchers have come to the conclusion that ingredients in the soybean have anticancer, antihypertensive, and anti-cholesterol benefits, and also act as a natural alternative to hormone replacement therapy.

Soy foods have become synonymous with health food and vegetarianism. Their popularity is tied to the belief that soy has “wonder-drug” benefits – so powerful that many people suppose they can safely eat their bacon and eggs for breakfast as long as they finish off their morning meal with a cup of soy yogurt.

However, there is a dark side to the soy story that warns that these foods may increase your risk for cancer, impair your thyroid, immune, and brain function, and cause you bone loss and reproductive problems. Fortunately, these worries are relevant mostly for people lured into consuming “fake foods” synthesized from man-made components of soy and other foods, and high potency soy supplements – not for those who consume traditional soy foods as a small portion of their diet.

Soy has estrogen-like activity that may promote the growth of estrogen-sensitive cancers (breast and prostate), especially for those people who already have cancer. Link to study.

Another study showed how 40 grams of soy or cow milk protein concentrate added to the diet significantly increases levels of a powerful cancer-promoting growth hormone, called Insulin-like Growth Factor 1. However, soy protein was almost twice as powerful as the milk protein concentrate – doubling the levels of IGF-1 with 40 grams of soy protein isolate. This growth promoter has been strongly linked to the development of cancer of the breast, prostate, lung, and colon. Excess IGF-1 stimulates cell proliferation and inhibits cell death – two activities you definitely don’t want when cancer cells are involved. Link to study.

The Bottom Line:

Here is the deal, aside from its natural harmful components, processed soy protein could also cause harm to the body due to its process of manufacturing. Knowing what I know now, I would not consume soy protein isolate on a regular basis. There are way better plant-based options out there. As always, I urge you to do your own research.