Vegetarians can get all the necessary nutrients from vegetarian food.
But it is not easy to get the full 100% and have to be careful with it to avoid dying naturally.
A well bear learn vegetarian is better in health than a meat eater.
I know 2 full vegetarian, 1 of them always lacking of some nutrients, but look the same, in body weight bmi as a meat eater.
While the other is very skinny only can see his bones.