I follow Dr. Mercola and have studied some research regarding soy as a product and as a toxin in the body. First of all, most soy is Genetically Modified, which is a whole eco issue unto itself, but secondly I do believe that unfermented soy is actually damaging to the thyroid and causes imbalance in the hormonal system. I'm excited about fermented soy products, like natto, miso, and tempeh, but I feel it's a serious issue for vegans/vegetarians if you have studied the harmful effects of soy.

As a caveat, Dr. Mercola does tout the benefits of eating small amounts of animal protein for various reasons, but aside from that I feel his research and opinions on food are valid and important, and usually not mainstream, which is why I appreciate him. He also touts eating raw as much as possible. From what I've found my body performs the best and feels the best with mostly vegetable and some kind of protein per meal, not much fruit, and no dairy or gluten. I try to steer clear of unfermented soy but I am wondering: if you eat a lot of soy product, have you noticed any negative effects?

Hm, that's kind of worrisome! For a while I was eating a lot of soy replacement products, like soy hot dogs & soy bacon, soy cheese, etc. I noticed that I was feeling really bloated and a little sleepy - like how everybody feels by the end of winter holiday pigging out? After I transitioned to a cleaner, more whole-food diet I haven't had that bloaty-sleepy feeling - but I do still drink soy milk and that doesn't seem to affect me in the same way.

I'll have to do some research - thanks for the heads up!

Fermented soy products like you mention are good such as miso etc.

But most other soy products have to be cooked which largely inactivates the goitrogens. So these are ok also, i dont know anyone who eats raw soyabeans which in large doses could cause some thyroid problems but they so could any goitrogen containing food such as the brassica family vegetables.

Cooking for even as little as 10 minutes inactivates goitrogens as does fermentation.

http://www.amlaberry.co.uk

Here's a link talking about all the dangers of soy, none of them being goitrogens or being based on cook times...Seems pretty legitimate to me! I'll be steering clear of soy...

http://www.naturalhealthstrategies.com/dangers-of-soy.html