Proteins 2 | MAY ‘25
Soy: A Safe, Healthy Protein for Every Diet
Soy gets a lot of buzz—some of it’s good, some of it is confusing. Decades of research shows one thing clearly: soybeans are a safe, nutritious protein for everyone. Whether you're plant-based or flexitarian, soy in all its forms deserves a spot on your plate.
Whole or Processed, Soy Delivers
Soybeans are one of the few plant proteins that are “complete,” meaning they contain all nine essential amino acids. You get this in whole forms like edamame, tofu, tempeh, and miso, as well as its byproducts like soy milk, soy yogurt, and soy protein isolate (what you find in protein powders). These foods pack high-quality protein, fiber, potassium, magnesium, and healthy fats—all without the saturated fat and cholesterol found in animal proteins.
Soy protein isolates are especially useful as a quick, digestible protein source after a tough workout. It scores almost as high as whey protein in bioavailability and supports muscle growth just as well. I personally make between 3-5 shakes a week using either soy or pea protein to supplement my diet and workouts.
Muscle Gains and Recovery
Contrary to old myths, soy is excellent for building and maintaining muscle. Multiple clinical trials show that soy protein supports muscle gains just as well as whey protein when combined with resistance training. Even older adults benefit: soy protein helps maintain lean mass and strength, proving valuable as we age.
Soy and Long-Term Health
Soy is often praised for its potential in heart health and cancer prevention. Whole soy foods contain phytosterols and fiber that can help lower LDL ("bad") cholesterol and research suggests that 25 grams of soy protein daily may reduce the risk of heart disease. Despite past fears about soy and breast cancer, newer studies show more promising outcomes. It has been showing that regular soy intake is linked to a reduced risk of breast, prostate, and other cancers. Additionally, in breast cancer survivors, moderate soy consumption is safe and may even improve outcomes—so much so that the American Institute for Cancer Research now endorses soy's safety.
What About Hormones?
Let’s clear this up: soy does not feminize men or lower testosterone. A meta-analysis of over 40 studies found no effect of soy or isoflavones on male hormone levels. There is also no evidence that soy causes "man boobs" or affects sperm quality in healthy men. The fears were based on weak, poorly conducted research, incorrect data, and unrealistic extreme cases (like drinking gallons of soy milk daily).
Safe Across Cultures and Ages
Soy has been safely consumed around the world for millennia. In East Asia, soy has been a dietary staple for centuries. Populations in Japan, China, and Indonesia eat multiple servings daily and show lower rates of heart disease and certain cancers. In the U.S., soy is widely used in vegetarian diets and increasingly in omnivorous diets, thanks to its convenience and robust health profile. Soy products are not just for adults, either. Soy-based infant formula has been studied for decades with no link to early puberty or hormone disruption.
The Bottom Line
Soybeans, whether whole or processed, are a protein source that supports muscle, heart, and overall health. Myths and exaggerated TikToks about hormones and cancer risk don’t hold up to legitimate scientific scrutiny. So go ahead and sip your soy milk, grill your tofu, or whip up your favorite soy protein shake. You're fueling your body with one of nature's most versatile foods.