Are you considering adding soy to your diet or even swapping out your conventional foods?  There is certainly plenty of publicity concerning soy, including its health benefits. Here you will find out why you should avoid soy? 

The sad fact is that this publicity has been generated by those looking to make a profit from soy. Are they really the ones best placed to look after your interests? 

For many years it’s been presented as a healthy alternative to meat, with the ability to prevent heart disease, child obesity, cancer and even weight gain. 

If the claims are true then we should all be eating it. Unfortunately, all is not as it seems. Here are some reasons why you should avoid soy. 

What Is Soy 

Soy is a miracle food, according to the soy production firms. On one hand they’re telling you that it will help you lose weight. On the other hand they’re telling farmers that it’s perfect for fattening up their animals. Can it really do both? 

Soy is actually a vegetable but it has been genetically modified; it’s hard to find a non-modified soy plant anywhere in the world! 

Soy is grown as a bean, and it is commonly added as a cheap protein to animal feed and ready meals.  

Negative Side Effects Of Eating Soy 

You might find it interesting to note that the soybean was considered unfit to eat until approximately 2,000 years ago; unlike most other vegetables. 

More importantly, the ancient thinking appears to be correct. There are several reasons why you should avoid soy: 

It Affects Your Thyroid Function In A Bad Way 

Soya milk has become a popular alternative to cow’s milk, yet it is extremely low in iodine and contains goitrogens.  

Goitrogens are present in all soy products, and act to depress your thyroid function.  

Iodine is an essential mineral to your body; it is part of the production process for thyroid hormones. Without adequate supplies of iodine your body will not produce enough thyroid hormones. 

These hormones are essential to a variety of functions in your body including controlling your metabolic rate. Insufficient amounts of these hormones will cause poor fetal development, fibrocystic breast disease and slow your metabolism. 

Unfortunately, the slowing of your metabolism will make it extremely difficult for you to lose weight. In fact, low thyroid activity is often associated with weight gain. 

You can find out more about my personal hypothyroid story here!

Affects How You Absorb Nutrients 

Soy has a high phylate content and research has shown that this compound prevents your body from absorbing magnesium, zinc, iron and calcium. 

As magnesium is essential to over 300 processes in your body (including those associated with hormones and metabolism), preventing its absorption cannot be considered to be a good thing. 

Can Causes Hormone Imbalances 

Soy contains phytoestrogens. This is a compound which is present in small amounts in many plants. However, it can be found in exceptionally high amounts in soybeans.  

The structure of phytoestrogen is very similar to the estrogen found in your body. In fact, it is close enough that your body cannot tell the difference. 

The problem with consuming soy is that it will increase the level of estrogen in your body, and throw off the balance between estrogen and progesterone.  

You might not think high estrogen is an issue, but consider this; research has shown that high levels of estrogen in women (and even in men), causes fat gain, bloating and water retention.  Worse, the presence of fat cells in your body will encourage more fat cells to be created; using estrogen! 

In short, soy can directly attribute to you gaining weight! 

weight loss and the birth control pill


94% of the soybeans produced in the US are genetically altered. This means that they can withstand the massive amounts of pesticides and herbicides used to kill bugs and other plants. 

The problem is that in doing this, glyphosate is added to the soybean. Glyphosate is a chemical which studies show is ‘probably carcinogenic to humans’.  

A carcinogenic is a substance that causes cancer. Definitely one to avoid! 

High Omega 6 

Soybean oil contains a high level of omega 6. Unfortunately modern diets already contain too much omega 6 (it’s the omega 3’s we want more of!). As omega 6 is known to cause inflammation and encourage fat storage, this is not going to help you lose weight. 

Products With Soy In 

The most obvious products will say ‘with soy’ or even have soy in the name. However, any product which has these ingredients in it will also contain soy: 

  • Gum Arabic 
  • Guar Gum 
  • Soy lecithin 
  • Textured vegetable protein 
  • Tofu 

There are many others with the word ‘soy’ in front of the ingredients, always check before you purchase! 

Summing It Up 

Despite excellent marketing by the manufacturers there is little doubt that soy has some serious side effects. These are not just detrimental to your goal of losing weight. They can also affect your general health and encourage you to gain weight. 

The best advice in this situation is to avoid products with soy in. A balanced, nutritious diet is a far better option whether trying to maintain or lose weight. I hope this article on why you should avoid soy helps :) Xx

Rachael is an Australian born certified personal trainer and nutritionist who holds a Bachelor degree in Science.

After struggling for years to find an exercise and diet program that is tailored to women striving for lean and toned body with no bulk she designed her Lean Legs Program. This program is tailored to each body type and focused on helping women get toned but feminine bodies, without getting bulky.

Her mission is to empower women and help them stay in shape in a healthy and balanced way.

5 Responses

  1. Hey Rachel,
    I use a protein powder by Amway called nutrilite and along with peas, one of the products is soy.
    a. Should I continue using it?
    b. Is Whey better?
    c. Suggest me some good protein powders.

    1. Hi lovely,
      There is some soy in our vegan meal plan as it’s one of the best sources of plant based protein. If you’d like to avoid it, feel free to substitute it with any other high protein food you enjoy (nuts, legumes and seeds). You can also find soy free tofu, but it’s a bit harder to find. xx


  2. Hello Rachael,
    I’ve just read your article about soy and I want to say thank you. That post has opened my eyes. But I have a question. I’m lactose intolerant and because of that I can’t eat or drink anything, where cows milk is contained. So I had to replace some products with soy. I was shocked that it could be so damaging to my health. I also didn’t know that it could stop my goal to lose some weight(which I’ve been trying for a long time). I‘m sure and I’m not exaggerating when I say that I consume many soy products daily. Can this really be a reason why I’m not losing wait? I want to change something about it. But I love to drink milk or eat yoghurt. Which products should I eat/drink instead?

    1. Hi lovely,
      This could be one of the reasons you aren’t losing weight. There are a few other potential reasons for not seeing results if you’re working out and eating healthy:

      If you have ever done any super low calorie diets in the past, this will affect your metabolism and make it harder for you to lose weight. And on the other end of the scale, binge eating prevents you from getting results too. I’m not sure if either of this situations apply to you, but it’s one thing to take into consideration.

      Sometimes weight loss isn’t just about calories in and calories out. Your body is a lot more complicated. Any issues with gut health, hormones, thyroid, cortisol or nutrient deficiencies can actually make a HUGE difference to your weight. Please have a read of this blog post as it explains these situations in more detail and you’ll be able to see if any of these sound like you.

      I would recommend trying out any other plant based milk products like almond, coconut, cashew, rice or flaxseed milk.


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