There has been much news recently about reports that soy is actually
bad for you. Most of those reports stem for problems with soy's protein
digestibility, which apparently are rendered moot in tofu, tempeh, soy
milk, and other slightly processed products, and from studies done on
animals, which fed the animals incredibly large amounts of soy from
birth and focused on creatures such as rats, who have very different
nutritional requirements from humans. Rats would also not do well
on human breast milk (with 5% protein vs. 45% protein in rat milk).
This is the equivalent of concluding that chocolate is a deadly poison for humans by testing its affects on cats. The
anti-soy articles also talked about how Asians really don't eat much
soy, as if all of Asia were one monolithic entity with 2.5 billion
people. Breaking it down into smaller groups, the people with the
highest lifespans on the planet, the Okinawans, eat quite a lot of soy
(12% of their diets for the elders), and studies done on them reason
that their soy intake is a big reason for their good health.
Here's a well reasoned retort
to the soy naysaysers from John Robbins, who wrote Diet for a New
America and The Food Revolution (and who has no relationship with the
soy industry).
Ultimately, eat things in moderation. Too many meat-eaters switch
to getting all their protein from soy when they become vegetarian or
vegan. Anything in excess is bad from you, whether it's spinach,
blueberries, or soy (all
"Superfoods"). Get your protein from lentils, beans, dairy (if lacto), eggs (if ovo), and other sources as well as soy.
And if you are a meat eater who is going to switch to being vegetarian,
do so slowly, as one of my friends did back in college. Every few
months he would make another day of the week be meat-free. This
allows both your body and mind time to adapt.