Soy is a legume. Legumes are not Paleo, but soy is among the worst of them. At least in America, it’s almost always genetically modified. Genetically modified foods have not yet undergone sufficient testing to make sure they’re safe for human consumption and they tend to be sprayed with pesticides much more heavily than conventional produce.
Soy is full of antinutrients, including phytates. Phytates are known to interfere with mineral receptors, preventing them from being able to absorb nutrients. This leads to nutrient deficiencies and cancels out any purported health benefits of legumes being high in minerals. Soaking and sprouting legumes can get rid of some of these antinutrients, but it can’t eliminate them entirely.
The Lesser of Several Evils
Like many legumes, consuming soy on occasion should be OK, but it’s not exactly a nutritious indulgence. Just make sure to eat them in their whole, organic form if you can, but those are increasingly hard to find.