Reader support is the lifeblood of Fighting Arts Health Lab. At no cost to you, purchases through links on this site earn us a commission.

Why Martial Artists Shouldn’t Have Soy

By Christina Major  |  2 Feb 2021

Soy protein drinks are all the rage in the martial art world. Steeped in the mysticism of Asia, soy has a reputation for replacing meat in a vegetarian diet.

But, just because it sounds good doesn't mean it actually is good. If you're consuming soy products in the US, chances are, you're doing your body more harm than good and negating your progress if you are following "The Fighter’s Nutritional Blueprint: Creating a Combat Arts Ready Body."

The History of Soy Around the World

Soy, soybeans, and fermented soy products seem to be a staple throughout Asia. But, that is a mysticism that's far overblown. According to the landmark study, then turned into a book, The China Study, Asians eat comparatively little soy compared to Americans. In fact, a typical vegetarian will consume between 12 and 16 oz of soy products per day—the typical Asian eats less than four ounces.

And there is one other big difference. In Asia, all soy is fermented. This includes tofu, natto, miso, and dozens of other products. Only edamame, raw soybeans remain unfermented; however, raw soybeans are a rare treat.

Founder of Seishin Martial Art Gi, Jesse Enkamp recommends a specific type of fermented tofu, and even that is only a small portion of a diet. He also recommends avoiding processed products, including soy protein drinks.

This is starkly contrasted with the United States. Most soy products in the United States are raw isolates and chemically created soy products. Additionally, 95% of all soy in the US is genetically modified. It's rare to find a traditionally fermented soy product outside of specialty stores and Asian markets.

Without being fermented, soy is incredibly dangerous to the human body. It's easy, cheap, but certain things just cannot be overlooked.

Why Soy Is Horrible for Martial Artists – Especially Female Athletes

When we're talking about soy here, we are talking about unfermented soy products. These are soy isolates, soy protein drinks, soy protein bars, and chemically produced tofu and vegetarian products. They are marketed to a health-conscious person but will have the opposite effect.

Biologically, soy disproportionately affects females more than males. Some of the chemicals within soy mimic estrogen, throwing off the natural hormones in the body. In women, throwing off this balance has greater effect than it does in men.

In particular, this affects breast tissue. For women, it dramatically increases the risk of breast cancer. In men, it can cause fatty deposits over the pectoral muscles, creating a breast. Although there are several causes of the 'man boob,' soy is one of the top causes.

And then there's the cancer aspect. Although for a long time soy was touted as a food that can help replace meat because meat was so bad for the body, now we are discovering soy is much worse.

Soy and the products they come from are directly linked to the onset of multiple different types of cancer, including:

  • Breast
  • Uterine
  • Bone
  • Thyroid
  • Prostate
  • Gastro-Intestinal
  • Any hormone-estrogen dominant cancer

Another aspect of soy that may contribute to the cancer risk is the prevalence of GMO soy. Just about every product you will purchase is genetically modified. Some studies have shown that in nearly every product tested, some residue of pesticides and other agricultural chemicals remained. Many of these chemicals, like RoundUp, are known to be carcinogenic. As such, you should consider using products, like Wildwood which is made from sprouted organic soybeans.

Finally, the biggest concern with soy is the goitrogens. These are a specific set of androgen-like hormones that are highly concentrated in the soybean.

During fermentation, these goitrogens are broken down. Fermentation plus a low intake of soy means that Asians do not experience cancer and thyroid problems like Americans do who eat unfermented soy.

What these goitrogens do is interfere with thyroid production and utilization. In some cases, they block the thyroid's ability to produce hormones. This inflames the thyroid and lowers your energy levels. In other cases, it interferes with the working of the thyroid hormones produced. As thyroid hormones have a primary focus on energy and metabolism, it's directly impacting your ability to work out and train properly. check out our article The Seven Foods a Martial Artist Should Never Eat.

So, Why Do They Say Eat Soy to Prevent Cancer?

You probably have noticed that doctors and many big hospitals produced literature that says soy can help prevent cancer. Why is there a difference of opinion?

It stems from the way the studies on soy are conducted. First significant detriment to most of the positive soy studies is that it is conducted on people who self-report their soy consumption but follow few other health markers. Scientists don't know if soy is why there is a lower breast cancer risk or if another factor, like exercise, might play a bigger role.

Although they consume soy more consistently in Asia than in the US, they get more exercise and eat a higher percentage of vegetables than in the United States. Additionally, the soy is fermented. The higher number of vegetables and the use of fermented soy negates the phytoestrogenic components and goitrogens.

More Vegetables Less Tofu | Fighting Arts Health Lab

Source: monticello, Standard License, via Shutterstock

Other studies follow a select group of women for a limited time to show breast cancer risk. Opponents of these studies say the studies were not conducted over a diverse population nor for the appropriate length of time.

Follow the Scientific Studies

More longer running studies are now showing breast cancer, heart disease, overall health problems increase the longer a person consumes soy in the US.

Finally, the majority of studies are conducted on isolated soy isoflavonoids given in specific concentrated doses. They do not factor in the other phytonutrients, phytoestrogens, or goitrogens that harm people. These studies don't look at real people eating real soy processed foods.

You don’t need soy, even on a plant-based diet. Special Forces elite trainer James Wilks is a mixed martial artist who follows a nearly pure plant-based diet and restricts soy consumption. His training helps hundreds reach elite levels.

If you're using a soy protein supplement to help you build muscle and have energy, you're actually doing the opposite. Over time, your thyroid will be damaged, and your risk of cancer goes way up. Although, as a martial artist, you do not need protein drinks or supplements at all, if you are using a soy drink, it's best to stop now. 

Loved this? Spread the word


About the Author

Christina Major

Christina Major, MS

Holistic Nutritionist, Naturopath & Herbalist

Christina Major is a holistic nutritionist, naturopath, and herbalist, and the founder of Crystal Holistic Health, where she has spent more than a decade helping clients improve their health through nutrition and whole-body wellness. She is also a lifelong martial artist with 18 years of training — a 2nd-degree black belt in Taijutsu who studied directly under the art’s Soke and senior Shihan in Japan, following earlier years in Tang Soo Do and Tae Kwon Do. At Fighting Arts Health Lab she writes on nutrition, recovery, and the demands of long-term martial arts practice.


Fresh Perspectives – Stories that Shift Views:

Far East, Lifestyle, Where We're Headed

Cebu ‒ World’s Arnis Capital & the Perfect Martial Arts Destination

By Sonia Ahmed  |  12 Sep 2020

Renowned as the queen of the South, Cebu is the port capital and the oldest city in Cebu province. Located in the Central Visayas, it’s the country’s most developed area, [...]

Lifestyle, Movies We're Watching

Johnnie To’s Throw Down Is the Love Letter Judo Always Deserved

By Éireann Mannino  |  16 Jul 2023

Despite the prevalent traces of Judo in modern martial arts action choreography, it remains sorely neglected as either a subject or primary martial art across the whole of cinema. Johnnie [...]

Strength and Conditioning Posts

Advanced Combat Arts Training Techniques Part III: Unconventional Methods for Extraordinary Results

By Lisa Stone  |  18 Mar 2025

How badly do you want it? I mean really want it? This is a question I've asked myself countless times throughout my martial arts journey. Because true mastery is attainable—but [...]

Lifestyle, Middle East, Where We're Headed

Behold the Unspoiled Beauty of Jeddah & it’s Budding MMA Scene

By Sonia Ahmed  |  19 Sep 2020

The Kingdom of Saudi Arabia has been making news for opening its borders for recreational tourism. Until 2018, it issued visas only for pilgrimages, business matters, sports events, and foreign [...]

Americas, Lifestyle, Where We're Headed

Chris Rini Finds Art in MMA Violence

By Jordan Newmark  |  14 May 2021

Imagine the sport of Mixed Martial Arts is a house. The foundation is the rules, the walls and floors are the fighters, and the roof is the promoters. Maybe, the [...]

Nutrition Posts

Top 12 Reasons To Add Fennel Seeds To Your Food

By Christina Major  |  30 Aug 2024

One of the primary ingredients in Dit Da Jow, fennel seeds are healthy and have massive health benefits that can help prepare you for a fight, may prevent bruising, and [...]

Europe, Lifestyle, Where We're Headed

Bataireacht – The Lost Art of Irish Stick Fighting

By Lewis Budden  |  21 Sep 2026

Ask most people to name an Irish martial art and you will get a blank look, or a joke about bar fights. That is our loss, and it is worth [...]

Lifestyle, Stuff We're Learning

Brazilian Jiu-Jitsu (BJJ): The Complete Guide for Beginners

By John Wes Green  |  3 Sep 2026

Every martial art claims it works. Very few prove it nightly, at full resistance, against someone genuinely trying to win. Brazilian jiu jitsu does, which is how a family art [...]

Injury Management Posts

Preventing Sudden Cardiac Arrests in Martial Arts

By Dr. Pamela Fernandes  |  14 Feb 2025

In June 2021, the world watched in horror as Danish footballer Christian Eriksen suffered a sudden cardiac arrest during a Euro 2020 match. This shocking incident highlighted the importance of [...]

Lifestyle, Oceania, Where We're Headed

Title Bout Aside, Mental Health Remains Megan Anderson’s Biggest Fight

By Jordy McElroy  |  31 Oct 2020

Megan Anderson fears no woman. Even with a scheduled December bout against Amanda Nunes — a two-division UFC champion that napalms faces for a living — a dauntless Megan Anderson [...]

Books We're Reading, Lifestyle

Mastering the Mat: Jiu Jitsu University Revolutionary Approach

By John Wes Green  |  25 Aug 2024

"Jiu-Jitsu University" by Saulo Ribeiro and Kevin Howell is a comprehensive and transformative guide to Brazilian Jiu-Jitsu (BJJ), authored by one of the sport's most accomplished and respected figures. Six-time [...]

Africa, Lifestyle, Where We're Headed

Explore Great Pyramids & Learn an Ancient Egyptian Martial Art Tahtib

By Sonia Ahmed  |  1 Sep 2020

Egypt is home to one of the world’s earliest civilizations. The country has seven UNESCO World Heritage sites. There’s hardly anyone in the world who doesn’t know about Egyptian pharaohs [...]

Workout Recovery Posts

Combat Arts Workout Recovery Hack – Stay Loose to Win!

By Lisa Stone  |  18 May 2021

Recovery techniques cover many bases. You do not want to wait until you are injured to start thinking about it. In fact, using proactive or preemptive recovery methods daily is [...]

Lifestyle, Staff Reviews

Feed Me Fight Me Is Marine Made to Help Veterans

By Jordan Newmark  |  6 Mar 2021

Feed Me Fight Me is all about the Mission.  For John Watkins and Brian Eayrs, who became friends while serving in the US Marine CORPS, their burgeoning business’ mission is [...]