Tip: The Worst Protein for Fit People

Brain atrophy, thyroid suppression, and decreased strength. Well, that's not good. Avoid this stuff.

Since protein can be scarce for those avoiding meat, soy is the vegetarian answer to a diet lacking muscle-building amino acids. It's also peddled as the cholesterol lowering replacement for "evil" red meat. We've not only been told that animal protein and saturated fat are bad, but we've been creatively convinced that plant proteins, like soy, are the solution.

Many are surprised to learn that the soybean itself is toxic to humans and livestock. It's one of the most heavily sprayed crops, and close to 93% of it is genetically modified if that's something that concerns you. Soy also contains isoflavones that mimic estrogen in the body (phytoestrogen), bind to estrogen receptor sites, and cause a host of health problems.

Hazards of Soy

  • Inhibits reproductive health
  • Alters brain function negatively
  • Suppresses thyroid hormone
  • Disrupts the endocrine system
  • Increases potential for breast and prostate cancer

Maybe this is why a study from the Journal of the American College of Nutrition found cognitive dysfunction and brain atrophy in men consuming two or more servings of tofu per week.

Researchers in the American Journal of Clinical Nutrition also found significant cell proliferation in breast tissue from soy supplementation in only 14 days. And a Japanese study at the Ishizuki Clinic found that just 35mg of isoflavones per day caused thyroid suppression in healthy individuals in just three months.

Sadly, most of the positive information we hear about soy is from companies marketing soy, or the governments controlled by them. It should never be treated as a meat or milk replacement, and selling it as an infant formula should be illegal.

In 1992, the Swiss Health Service estimated that two cups of soy milk per day provides the estrogenic equivalent of one birth control pill... and infants fed soy formula the equivalent of five birth control pills.

And even if we look strictly at performance, soy protein has been shown to decrease muscular strength, lower testosterone and increase cortisol when consumed post-workout. The exact opposite of what we get from meat and dairy, and the exact opposite of what we need to live a longer, stronger life.