I understand doing it for moral reasons, but becoming vegan (or even vegetarian) for health reasons is not the right way to go. You can look up studies on this, including the fact that children raised vegan have serious and possibly permanent neurological damage. You may feel better temporarily as a placebo effect. Or because you associate feeling morally good with feeling healthy, the same way marathon runners feel "good" even though running marathons or long-distance running in general is one of the worst things you can do to your body. But I guarantee you, you are not healthier because of being vegan or vegetarian.
I'd like to see these "studies" you're talking about. My guess is if you look deep enough, you'll find dubious backing for them (assuming they even exist). There are massive amounts of mis-truths and propaganda about vegan and vegetarian diets. This is one of them.