Yes. But possibly not as you think.

People who become vegans, are already in that direction before they become. Then they become vegans and get even more in that direction.

What is that direction? It's a weakness that makes them think that they can get enough nutrition without eating meat and dairy. It only makes their thinking health worse, so that they become more vegan than ever.

If they ate dairy and meat in right proportions, they might lose the illness that causes them to become vegan.