Check out CaveGirlEats' post (over at Steve's Original) explaining why -- despite what you've heard -- soy is bad, bad news. She offers ten reasons why soy is terrible for you. Most notably:
The soy industry has worked tirelessly to discount the studies indicating that soy can have an estrogenic affect via its isoflavones, or phytoestrogens (plant-based estrogens). Don’t be fooled. Soy can lower testosterone levels in men. Monks regarded tofu as an aid to neutralizing sexual urges. Monsanto’s Genetically Modified soybeans were fed to cows who subsequently produced more milk, indicating a hormonal boost from these plant estrogens and proving that soy is a potent hormone disregulator.Somewhere on my gargantuan Paleo page, I also discussed why soy is crap. So I beg of you: Pour out your soy milk, replace your soy sauce with coconut aminos, and think of all the reasons you don't want to end up like Jeremy Piven.