Over the past few years, T-Nation has published several articles on the drawbacks and possible dangers of soy, beginning with a groundbreaking article by TC that first appeared on the site in 2000. When we first began running these articles, many critics thought we were way off base. After all, isn't soy a miracle food with numerous health benefits? Doesn't it prevent diseases, retard aging, and make you supermodel skinny?

The answer we gave was "no." But the critics kept on soy-bombing us, some even accusing us of bashing soy simply because we didn't sell it in our online store (which is ridiculous because we could sell it if we wanted to, and make a higher profit off of it than the quality whey/casein blends we do sell).

Honestly, we didn't worry about it too much. We suggested that bodybuilders and fitness enthusiasts avoid supplementing with soy-based protein powders and left it at that. Then something big happened: Atkins took over the world. Low carb diets became all the rage and food manufacturers did the dance of supply and demand, stocking the shelves with low carb foods – foods very often packed with soy.

So how bad is this stuff? Bad enough that Dr. Kaayla T. Daniel has written an explosive new book about it called The Whole Soy Story.

T-Nation recently had a chance to sit down with Dr. Daniel and talk about this controversial subject.

T Nation: Before we get started, tell us a little about yourself and what you do.

Dr. Kaayla T. Daniel: I'm a CCN, a Certified Clinical Nutritionist. I also just received my Ph.D. in Nutritional Sciences and Anti-Aging Therapies. I design diet, supplement, and lifestyle plans for private clients and also teach classes, seminars, and workshops on everything from anti-aging to natural ways to reverse ADD and ADHD. Right now I'm most often asked to talk about The Whole Soy Story.

T Nation: Why write a book on soy?

Dr. Daniel: I decided to write this book because I saw so many clients and friends suffering from vegetarian and near vegetarian diets. Most often the chief culprit was soy. The Whole Soy Story is based on my dissertation so there never was any question that I'd have to base every claim on hard science.

T Nation: Before we talk about the dangers of soy, let's back up a bit and talk about what soy is and where it came from.

Dr. Daniel: Soybeans are beans that grow in fuzzy green pods. They come in many colors but most are a yellowish tan color and marked with a single, distinctive black eye – nature's way perhaps of giving us a warning!

Traditionally, Asian soybean plants were not grown to be eaten but to be used as "green manure" – as a cover crop designed to be plowed under to enrich the soil between plantings of the crops used for food. It was a fertilizer. It wasn't until the Chiang Dynasty that the Chinese came up with the fermentation methods needed to tame the soybean's undesirable elements and make it into a food.

The soybean paste known as miso came first, followed by soy sauce, which was discovered as part of the miso-making process. Other soy foods such as tofu, tempeh, and natto came much later, around 1000 AD.

In the West, the soybean has mostly been used for its soy oil, which is what you get in most products labeled vegetable oil, margarine, or shortening. Soy here is a product of the industrial revolution – an opportunity for technologists to develop cheap meat substitutes, to find clever ways to hide soy in familiar food products, to formulate soy-based pharmaceuticals and to develop a plant-based renewable resource that could replace petroleum-based plastics and fuels. This last could be good for the planet.

T Nation: So how did soy become known as such a "health" food?

Dr. Daniel: For years, the soy protein left over from soy oil extraction went exclusively to animals, poultry, and more recently fish farms. The problem is that only so much soy can be used in the feeds before the animals start developing serious reproductive and other health problems. So the soy industry still had a lot left over and decided to start marketing it as a "people feed."

T Nation: I remember first seeing soy as an ingredient in discount dog foods. How did it go from dog food to people food?

Dr. Daniel: Well, for this to succeed, they had to improve soy's image from that of a poverty food or hippie food. Back in 1975 a top-gun marketer hired by the soy industry recommended that the fastest way to get poor and middle class people to accept a product was to have it consumed on its own merit – not just because it was "cheap" – by people who were affluent enough to buy any foods they wanted. Accordingly, soy is aggressively marketed as an upscale "health food."

The United Soybean Board has targeted key influences such as food manufacturers, chefs, dietitians, editors, writers etc., and has aggressively lobbied in Washington and has invested millions in medical research. They spent more than a million dollars on establishing the FDA's spurious cholesterol lowering heart claim alone. The campaign has been nothing less than brilliant.

T Nation: So it seems. Now, generally speaking, why are you suggesting that everyone avoid soy?

Dr. Daniel: Most of us don't need to avoid it completely, and a good thing too since it's in just about everything these days: Bumblebee canned tuna, Hershey's chocolate, readymade spaghetti sauces, muffins.... Soy can be found in more than 60 percent of the goods sold in supermarkets. Anyone who's eating processed, packed, or canned foods is probably getting some "hidden soy." It's even been called the "stealth ingredient."

Those who need to avoid soy completely are people with soy allergies. These people can experience adverse reactions from even a trace of soy. For the rest of us, the goal would be to avoid modern soy products like readymade foods such as energy bars, veggie burgers, "low-carb" pastas, chilis, and other things containing soy protein isolate, soy protein concentrate, texturized vegetable protein, or other industrial-age soy products.

The soy industry has convinced a lot of people that anything with soy in it must be super healthy. The truth is these are highly processed junk foods. I also recommend against soy milk and other soy dairy products. The problem goes beyond soy. Take a good look at the ingredient list of soy milk or soy ice cream. Lotta sugar!

T Nation: Is one type of soy worse than the other?

Dr. Daniel: Yes. Old fashioned soy products such as miso, tempeh, natto and shoyu or tamari soy sauce are fine when eaten occasionally. My two children and I enjoy them in our house. The fermentation process deactivates some of the anti-nutrients in soy that cause digestive distress and mineral loss. Most of the better brands of these products are also made with organic soybeans.

Tofu isn't fermented and so is not so good for us, but a little once in a while isn't a problem. The worst products are the modern soy foods manufactured using high tech processes. These products have been subjected to very high heat, pressure, and chemicals. There's nothing "natural" about them.

T Nation: Let's get specific. Why should men, especially weightlifting studs like we guys here at T-Nation, avoid soy?

Dr. Daniel: Soy lowers Testosterone levels! Just about all soy products on the market contain the phytoestrogens (plant estrogens) known as isoflavones. Plant estrogens have lowered Testosterone levels in rats, monkeys, and other animals as well as humans. For grown men, this usually leads to decreased libido and lower sperm count. There's an old wives tale that Japanese women punish their straying husbands by feeding them a lot of tofu!

We can joke about that but not about the effect on baby boys fed soy formula. Pediatricians are reporting more and more cases of emasculated boys reaching puberty with breasts and tiny penises. Undescended testicles are also far more common than they were in the past. Remember too that soy estrogens damage far more than the reproductive system. The thyroid is usually hurt first, leading to loss of energy, weight gain, depression, lethargy, and a host of other symptoms.

T Nation: That's some frightening stuff! Although you'd never hear this in the popular press, soy isn't good for women either, is it?

Dr. Daniel: Many men have avoided soy because they've had the idea – rightly as it turns out – that "real men don't eat tofu." Women, on the other hand, have been sold on the idea that soy will fix anything that ails them.

I've worked with a lot of female clients who are purposefully adding large doses of soy to their diets. A lot of them chug soy milk morning and evening and eat energy bars on the run. When they come to me, they complain of fatigue, depression, hair loss, poor skin and diminished sex drive. When I encourage them to go to their doctors to have their thyroids tested, they almost always are diagnosed with low thyroids – hypothyroidism.

Women who eat a lot of soy are also more likely to have reproductive system problems – heavier menstrual flow, increased cramping, infertility, as well as the loss of sex drive mentioned earlier. There are increasing reports of a painful urinary tract condition known as interstitial cystitis and a painful condition called vulvodynia or vulvardynia. This last refers to pain of the external female genitals – excruciating pain that's often so severe that sex is impossible.

Finally, we're getting more and more reports of vegan mothers giving birth to sons with hypospadias.

T Nation: I hate to ask, but what is that?

Dr. Daniel: That's an estrogen-induced birth defect in which the opening of the penis is on the underside, located anywhere from near the tip of the penis to right up at the crotch. These cases are tragic. Although estrogens in the environment have also been implicated, it's prudent for pregnant women to avoid ingesting soy estrogens.

T Nation: What about soy in infant formulas?

Dr. Daniel: Infants on soy formula are extremely vulnerable. Remember that soy formula constitutes most, if not all, of their diets. Based on figures from the Swiss Federal Health Service, some of my colleagues have calculated that an infant on soy formula is getting the hormonal equivalent of the estrogen found in three to five birth control pills every day! That's a lot of estrogen, and this amount is especially dangerous for infants whose very development requires the right hormones in the right place at the right time.

Studies on rats, sheep, monkeys and other animals suggest that the estrogens in soy infant formula can irreversibly harm the baby's later sexual development. And this is exactly what we're hearing from both parents and pediatricians.

T Nation: Don't baby boys experience a large Testosterone surge during the first few months of life?

Dr. Daniel: Yes, all that Testosterone is needed to program the boy for puberty, the time when his sex organs should develop and he should grow facial and pubic hair and start speaking with a deep voice. However, if receptor sites intended for the hormone Testosterone are occupied by soy estrogens, appropriate development may be delayed or may never take place.

For girls, soy formula has the opposite effect. It's likely to accelerate puberty and may cause reproductive difficulties later in life. The studies that supposedly prove that infants on soy formula develop normally consider only height, weight and other measurements of growth as measured in infancy and early childhood. Many of the negative effects don't become obvious until puberty.

T Nation: Okay, let me play devil's advocate for a minute. One of the arguments supporting soy always brings up the apparent health and longevity of soy-eating Asian cultures. What do you say to that?

Dr. Daniel: First of all, Asia is a huge continent. It includes people of very different cultures with widely varying dietary customs and health records. If we look at the statistics for cancer and other diseases, we discover that certain types of cancer are more prevalent in the United States than in, say, China, and vice versa. Though the soy industry likes to take credit for the good news, it consistently neglects to mention the bad. And for all anyone knows, the good news could be attributed to other dietary or lifestyle influences. Claims that soybeans have been a major part of the Asian diet for more than 3000 years, or from "time immemorial" as we sometimes hear, are also simply not true.

The main point I want to make is that Asians don't actually eat very much soy.

Peter Golbitz, of Soyatech Inc, a soy-industry information center, reports that the average consumption per year in China, Indonesia, Korea, Japan and Taiwan ranges from 9.3 grams to 36 grams per day. Compare that to a single cup of tofu that weighs in at 252 grams and think about the people you know who are eating soy every day, several times a day.

Others too have reported that Asians eat very little soy. When T. Colin Campbell of Cornell University traveled around China to survey the dietary habits of 6,500 adults in 130 rural villages, he reported that they ate an average of 12 grams of legumes per day. Probably only about one third of this amount is soy. (For some inexplicable reason he never got the figures on soy alone.)

Finally, keep in mind that the type of food Asians eat is very different from the soy that's appearing on the American table. Think small amounts of old-fashioned whole soy products like miso and tempeh, not soy sausages, soy burgers, chicken-like soy patties, TVP chili, tofu cheesecake, packaged soymilk or any other of the ingenious new soy products that have infiltrated the American marketplace.

T Nation: Since soy is getting hard to avoid, is there a minimum intake you'd suggest? How many grams per day are okay?

Dr. Daniel: Total grams can be hard to calculate because of all the hidden soy in packaged and restaurant and deli foods. This type of soy can be avoided by preparing fresh, whole foods from scratch.

I'd say that people who are healthy can safely eat several small servings of soy foods per week, preferably the old-fashioned foods such as miso, tempeh and natto. They can also safely use shoyu or tamari soy sauce as a condiment. Those are found at health food stores and are far superior to the soy sauces sold at supermarkets. I wouldn't exceed an average of 36 grams per day – an amount equivalent to what's ordinarily eaten in Japan, which is the country with the highest soy consumption in Asia.

T Nation: When we first started writing about the dark side of soy, we were attacked from many different directions, mainly from those who sold soy protein. Have you experienced any backlash because of your views on soy?

Dr. Daniel: My news really upsets some vegans, but even some of the vegan websites are getting wise to soy. Chet Day's site is one that dares to tell the truth. In my experience, most non-vegetarians are enormously relieved when they learn that they don't need to eat soy. These people loathe the "beany" taste of soy products and the side effects such as cramps and flatulence.

People who've harmed their thyroids or experienced other serious health problems because of soy can get very angry, but not at me. The backlash is against the soy industry.

T Nation: Understandable. It seems soy has taken on a new role now that everyone is going low carb. Why exactly are so many low carb foods being stuffed with soy?

Dr. Daniel: Soybeans have a lower carbohydrate content than other beans, but the main reason is that the food industry has lots of soy protein left over from soy oil manufacturing. Soy protein is cheap! The soy industry has convinced the public that it's "healthy" and desirable. The current low carb fad has made it possible for the soy industry to stop trying to hide the soy that goes into pastas, breads, chips, cereals, etc., increase the content and brag about it!

T Nation: In your book, you write about "hidden soy" and "undeclared soy content" and "aliases." Sounds scary. What is all that exactly?

Dr. Daniel: It's very scary, at least for people with soy allergies. As I mentioned before, there's at least trace amounts of soy in the majority of supermarket and health food store products. People who are allergic must avoid all soy and can experience terrible allergic reactions from even a trace of it.

T Nation: Are a lot of people allergic to soy?

Dr. Daniel: Soy is now one of the top eight allergens and some experts put it as high as in the top four. People with the highest risk are children who are allergic to peanuts and have asthma. There have been fatalities because of hidden soy.

By "hidden soy" I mean soy where you wouldn't expect it. For example, the soy protein found in Bumblebee canned tuna, in a fast-food burger, whipped cream or in a loaf of bread.

By "undeclared soy" I mean soy that's not listed on food labels. For a variety of reasons, labels aren't always accurate. Manufacturers can be careless and neglect to mention soy. Perhaps the recipe was changed and the label hasn't caught up.

Undeclared soy is also a possibility from cross-contamination caused by soy used in other products produced at the same facility. For people with soy allergies, soy dust in the air from the bulk bins at health food stores can be a problem. So can a trace amount of soy that has rubbed off from cardboard packaging in which soy protein isolate has been used as a bonding ingredient.

By "aliases" I mean commonly used ingredients that people don't recognize as soy. Some good examples would be "textured vegetable protein "or "boullion" or "vegetable oil." These may or may not contain soy – usually they do.

T Nation: What do you think about this: certain soy products can now sport a heart-healthy label from the US Food and Drug Administration. The new claim says something like "25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease."

Dr. Daniel: I think 25 grams a day will harm your thyroid! That's a proven risk supported by dozens of well-designed studies. Furthermore, thyroid disease is itself a risk factor for heart disease. Cholesterol level has never been an accurate marker of heart disease risk. Homocysteine levels, c-reactive protein, lipoprotein (a) are all more telling.

As for saturated fats, it's the artificially saturated fats – the hydrogenated fats full of trans fatty acids – that are dangerous to heart health. These come from vegetable oils, mostly soy oil, not from animal products.

Now about that FDA heart health claim.... The FDA bills itself as "The Nation's Foremost Consumer Protection Agency" and its mission statement ends with the phrase "helping the public get the accurate, science-based information they need to use medicines and foods to improve their health." Yet the handling of this dubious claim suggests nothing so much as an unholy alliance with big business.

T Nation: "Unholy alliance?" Those are fightin' words. Do tell.

Dr. Daniel: The original petition submitted by Protein Technologies International requested that the health claim be made for the soy isoflavones, the plant estrogens found abundantly in soybeans. Provided with only weak and conflicting proofs that isoflavones lower cholesterol and besieged by strong evidence of toxicity and hormone disruption, the FDA should have thrown out the PTA petition. It had a duty to do so.

Instead, the agency took the unprecedented step of rewriting PTI's petition and substituting a claim for soy protein. This step violated the industry's own regulations. Then the FDA speeded the decision-making process by reducing the time in which members of the public could protest to only 30 days. In doing so, they disregarded the testimony of top scientists at the FDA's own National Center of Toxicological Research, British government researchers and other qualified experts providing strong evidence of danger from allergens, protease, inhibitors, and other soy components as well as the plant hormones.

It's all the more shocking because the FDA never had good evidence of soy's cholesterol lowering effect to begin with! It relied almost entirely on just one study – a 1995 meta analysis of 29 studies by James W. Anderson that was sponsored by Protein Technologies International.

T Nation: This is starting to sound like a big conspiracy. I can't help but think all this positive press and the use of mega amounts of soy in regular foods isn't padding someone's pockets. Is there a "Big Soy" out there to go along with "Big Tobacco?"

Dr. Daniel: The little soybean is big business. Soy foods are one of the fastest growing sectors in the food industry with retail sales growing from $0.852 billion to $3.2 billion during the decade from 1992 to 2002. In order to accomplish this, the soy industry had to convince a lot of people that soy is good for them. To do that they've had to cover up and suppress a lot of evidence to the contrary.

T Nation: Lots of money changed hands under the table it sounds like. How can T-Nation readers find out more and get their paws on your book?

Dr. Daniel: I'd like to welcome T-Nation readers to my website: www.wholesoystory.com. The site includes several free chapters from the book, questions and answers and other good info. People who order a prepublication copy can download the book and read it right now. Anyone who wants the references backing what I said today will want to do this. Once the book itself is printed, I'll send them an autographed copy about a month before it becomes available in bookstores or on Amazon.

Web buyers will also get a free copy of my newsletter, with updates on foods and products to avoid. I'm also using my website to collect stories from people who have been harmed by soy.

T Nation: Thank you very much for chatting with us today, Dr. Daniel. It's been, well, scary.

Dr. Daniel: My pleasure. Thank you, Chris.

Chris Shugart is T Nation's Chief Content Officer and the creator of the Velocity Diet. As part of his investigative journalism for T Nation, Chris was featured on HBO’s "Real Sports with Bryant Gumble." Follow on Instagram