Soyfoods aid longevity. Although a few authors dispute this, most literature found on the reputable internet sources show that traditional soyfoods, especially those with live cultures, correlate with reduced risks of various diseases without negative side effects. But the maximum benefit comes from using soy foods to replace a large fraction of the diet normally occupied by high sources of saturated fats.
In other words, don't just add soymilk and soy shakes, soy based artificial cream oppings to your diet. Instead, replace 30 to 60 percent of your red meats with tofu, miso, tempeh, edamame, and so forth. Also use baked, broiled, or grilled chicken, fish, and other foods that are not fried.
Soy Beans are unique in the plant world, in that they provide all of the "essential" amino acids (proteins) and fatty acids that the human body can not make, plus numerous "plant hormones" that protect against various ailments, such as cancers, diabetes, heart disease, memory loss, menopause, osteoporosis, PMS, stroke.