For years, soy has been marketed as a miracle superfood—high in protein, heart-healthy, and a staple in plant-based diets. But is it really the health-promoting powerhouse it claims to be? The truth is, soy is highly estrogenic, genetically modified, and a potent goitrogen that can disrupt thyroid function. While fermented soy like natto has been traditionally consumed in Japan, most soy in the U.S. is ultra-processed, GMO-laden, and hidden in everything from protein powders to infant formula.
If you're still reaching for tofu over steak, keep reading—because once you see what soy is really doing to your body, you might rethink that soy latte.
Scientists Used Soy Isoflavones to Turn a Male Catfish Completely Female
Need proof that soy impacts hormones? Japanese researchers successfully turned male catfish into females using a compound found in soy.
This isn’t a conspiracy theory—it’s a documented experiment. The research team from Kindai University exposed catfish to soy isoflavones, the same plant estrogens found in tofu, soy milk, and many vegetarian "meats." Over time, the male fish transitioned completely into females.
If soy has this profound effect on fish, imagine what it could be doing to human hormone balance, testosterone levels, and reproductive health over time.
The Catfish Experiment: How Soy Alters Biology
In a 2021 study, researchers at Kindai University in Japan discovered that exposing male catfish to genistein—a soy-derived isoflavone—could fully feminize them, resulting in an all-female population.
The reason? Genistein mimics estrogen in the body, altering hormone signaling and disrupting normal reproductive function. While this study focused on fish, it raises serious concerns about the widespread consumption of soy-based foods, especially in men and developing children. If a steady dose of soy can completely change the sex of a fish, what is it doing to human testosterone and fertility levels?
Read the full study here: Mainichi.
High-Soy Diets Drop Testosterone by 15%
Soy’s estrogen-mimicking compounds don’t just affect fish—they have a direct impact on male testosterone levels. Studies show that high-soy diets can cause a 15% drop in testosterone, leading to symptoms like:
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Decreased muscle mass
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Increased body fat
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Low libido and erectile dysfunction
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Mood instability and brain fog
For men looking to maintain optimal strength, virility, and overall health, a soy-heavy diet may be working against you.
Before Soy: Strong Men Dominated the World
Look back at photos of men in the early 1900s, before soy protein and fake meats infiltrated the food supply. What do you see? Strong, lean, masculine physiques. They ate meat, eggs, dairy, and organ meats—not tofu, soy protein isolates, and seed oils.
Compare that to today’s modern diet, where processed soy products dominate plant-based diets. The result? Skyrocketing obesity, lower testosterone, and fertility issues. Could ultra-processed soy be contributing to this decline?
Japanese Housewives Knew What Soy Could Do
Soy has long been recognized for its effects on male fertility—so much so that Japanese housewives historically fed their husbands extra tofu when they feared infidelity or unwanted pregnancy.
The phytoestrogens in soy lowered testosterone levels and reduced fertility, making men less virile over time. If traditional cultures understood soy’s suppressive effects, why are we ignoring this knowledge today?
Men Who Consume Soy Have 2-3 Times Less Sperm
If you care about fertility, this should make you think twice before consuming soy. A Harvard study found that men who ate soy regularly had 2-3 times lower sperm counts than those who didn’t.
With sperm counts already plummeting in the modern world due to environmental toxins, microplastics, and poor diets, why add a known sperm-suppressing food into the mix? If you want to optimize reproductive health, skip the soy and eat real, nutrient-dense foods.
Soy Formula = Estrogen Bomb for Babies
This is one of the most shocking facts about soy: Babies fed soy-based formula receive the estrogen equivalent of 5 birth control pills per day.
Let that sink in.
In males, this can suppress proper sexual development, leading to lower testosterone and feminization. In females, it has been linked to early puberty and hormonal imbalances. The delicate hormonal system of an infant should never be exposed to such high levels of estrogenic compounds.
There is no biological need for soy-based formula—better alternatives exist, including raw milk and homemade formula recipes based on traditional nutrient-dense foods.
Steak Over Soy: The Nutritional Power of Meat
Steak is superior to soy in every way.
Here’s how they compare:
| Nutrient | Steak (100g) | Soy (100g) |
|---|---|---|
| Protein | 25g (highly bioavailable) | 12g (incomplete protein) |
| Iron | Heme iron (easily absorbed) | Non-heme iron (poorly absorbed) |
| Zinc | 5 mg (boosts immunity & testosterone) | 0.9 mg (low bioavailability) |
| Vitamin B12 | 2.1 mcg (essential for brain & nerves) | 0 mcg (soy contains none) |
| Choline | 85 mg (critical for brain function) | 24 mg (much lower) |
| Saturated Fat | 5g (supports hormone production) | 0.5g (lacks saturated fat benefits) |
Steak delivers superior protein, iron, zinc, B12, and healthy fats—all in a form your body can actually absorb and use. Meanwhile, soy is an inferior, estrogenic, and poorly absorbed protein source that lacks critical nutrients for human health.
The Verdict? Skip the Soy, Eat the Steak
The modern world wants you to believe that soy is a superfood while demonizing meat, eggs, and animal fat. But history and science both tell a different story.
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Soy is highly estrogenic
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It disrupts testosterone and fertility
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It’s overwhelmingly GMO and processed
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Steak and animal foods are nutritionally superior
If you want to build strength, support hormone health, and nourish your body with real food, ditch the soy and choose steak instead.
Your body will thank you.
Citations:
- Ineno, Toshinao, et al. "Researchers in Japan Use Soybean Compound to Make Catfish 100% Female." The Mainichi, 26 May 2021, https://mainichi.jp/english/articles/20210526/p2a/00m/0sc/014000c.
- "Creating All-Female Catfish Without the Use of Hormones." The Fish Site, 27 May 2021, https://thefishsite.com/articles/creating-all-female-catfish-without-the-use-of-hormones.
- Goodin, Susan, et al. "Clinical and Endocrine Effects of a High-Soy Diet in Men with Prostate Cancer." Journal of Clinical Oncology, vol. 25, no. 21, 2007, pp. 3060-3066. https://ascopubs.org/doi/10.1200/JCO.2006.09.4036.
- Chavarro, Jorge E., et al. "Soy Food and Isoflavone Intake in Relation to Semen Quality Parameters among Men from an Infertility Clinic." Human Reproduction, vol. 23, no. 11, 2008, pp. 2584-2590. https://academic.oup.com/humrep/article/23/11/2584/2915671.
- Irvine, C. H. G., et al. "Phytoestrogens in Soy-Based Infant Foods: Concentrations, Daily Intake, and Possible Biological Effects." Proceedings of the Society for Experimental Biology and Medicine, vol. 217, no. 3, 1998, pp. 247-253. https://journals.sagepub.com/doi/10.3181/00379727-217-44261A.