This can be a very controversial topic. Everyone seems to have a difference of opinion on soy so it can be confusing for people to find accurate information and make an informed decision on whether to include soy into their diet or not. I will explain to you how I have come to know soy.
Many people avoid soy products because they contain phytoestrogens which act similar to estrogen within the body. Some people perceive this as a bad thing but recent research has shown that phytoestrogens from plants actually decrease the negative effects of too much estrogen in the body, lowering our risk of breast, prostate, and other reproductive cancers. It's also interesting to me that the same people who avoid soy for its phytoestrogens do not seem to be concerned about the hormones in dairy or animal meats. A specific example of when you would want phytoestrogens in your body is for women going through menopause. Phytoestrogens from soy and other plants are known to help balance hormones and reduce side effects of menopause that occur from low estrogen levels such as hot flashes and depression. Soy is also a great source of plant based protein and is very versatile for cooking as it easily takes on the flavor of anything you cook it with.
Soy itself is a whole food (soy beans). The problem with soy arises when we fragment and over-process it creating and consuming protein powders, energy bars, and fake meat products. Especially look out for soy protein isolate on food labels. Most soy is grown with many pesticides and herbicides and come from genetically modified seeds (GMO's). But all that being said, it doesn't mean you should avoid soy all together, just be a smart shopper!
It's important to buy organic GMO free soy products that have been minimally processed such as soy beans, edamame, tofu, and miso. Avoid the fake meat products. Another great soy addition is tempeh, which is simply fermented soy. It's more easily digested and contains more enzymes and probiotics.
The bottom line is simple when it comes to soy and all foods... for optimal health, eat plant based foods in their whole-food form!