When I first moved into the college dorms, one of my favorite meals was Special K (with those freeze-dried "berries") floating in tan-colored soy milk. It was healthy and I thought it tasted pretty good. Looking back I shudder because it was quite clearly the culprit in many of the stomach issues I had, as it was rich in the dreaded Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAPS).
Once I realized that soymilk was one of the major causes of the bloating and other fun stuff I struggled with, I never bought soy milk again.
But I've never been anti-soy. In fact, I can't imagine life without the culinary treasures of soy sauce and miso. For me, changing my diet was about shifting staples, not clamping down on the margins. I'm only willing to do that if absolutely necessary. I don't think soy is a problem unless you are getting a large percentage of your calories from it.
And through my explorations of Asian cuisine I've come to appreciate soy for what it, which is a potent substrate for fermentation. That's why soy milk upset my stomach so much. But luckily, long ago someone figured out how to ferment it outside the body, creating rich salty flavors that characterize miso and soy sauce.
It's by no means a recent food. There is new evidence that humans were using wild soybeans 9000 years ago and that domestication occurred 5,500 years ago.
American vegetarians embraced Asian soy products a long time ago, but it wasn't until I started actually eating authentic Asian food that it struck me on how much they were missing out on. In Asian cuisine, soy is an extender of animal and seafood products, creating potent health and flavor synergies.
If you think tempeh is just some bland crappy paste-board-like soy concoction, you need to fly to Amsterdam and have homemade tempeh in a rich briny fermented shrimp and black pepper sauce. I've never ever had tempeh like that in America.
And I've found that even unfermented soy doesn't really bother my stomach. Oh, but only when it's served in a Korean restaurant that makes broth from scratch, boiling animal bones for days to achieve a creaminess, then boiling fresh homemade tofu and chunks of ox blood in the broth. It's digestible and much more delicious than it sounds, particularly when you pour some of the homemade kimchee into the broth.
Another unsung hero in Korean cooking is fermented soybean-red pepper paste, Gochujang, which makes sriracha seem bland. It works so well with beef that it's heresy to put it on some vegetarian brown rice gunk. It almost always contains barley though, so stay away from it if you don't eat wheat, though I'd wonder how much of it could be harmful because fermentation can destroy gluten.
And really, there is nothing like liver or beef belly marinated in soy sauce. I know some folks use coconut aminos because they think they are reacting to soy sauce, but I don't think there is much in most soy sauce to react to, except for amines, which are present in coconut aminos too.
But Asian food hasn't been immune for the industrialization of soy products, which leads to general mediocrity and upset stomachs all across the globe. The latest issue of my new favorite magazine, Lucky Peach, has an amazing article about miso. There are a great many types of miso, but the miso that most Asian restaurants serve is a powdered, pasteurized, fortified, bleached concoction that barely deserves to be called shinshu miso. But it's bland, ships easily, stores easily, and requires no skill to make into soup.
The same thing has happened to broth and many other traditional foods. It's hard to find a restaurant that makes its own broths with bones rather than a powder containing MSG and other assorted non-food additives. Many Koreans now make a Gochujang that isn't fermented at all.
The only good trend is the post-WWII trend of combining butter with miso or soy sauce. You can create some incredibly rich and wonderful sauces this way. I just now enjoyed some scallops with a soy-sauce browned butter glaze.
For me the fascinating thing about soy sauce and miso is how deep and rich the flavors are, yet they do not compel me to overeat. I think it's a function of their complexity. They are delicious, but have an underlying funkiness. It's important, like fish sauce is to SE Asian cooking, but you definitely don't want to overdo it.