Question for experienced hairdressers!

When I first went to my current stylist one of the first things he said to me was “are you vegetarian?” And I was shocked that he could tell that by my hair.

I had an appointment the other day, I hadn’t seen him in a while. While he was looking at my hair he asked me if I had changed my diet, I responded with “kind of” then I had made a comment later on how my sisters hair is extremely long and healthy and she has chopped it short a few times and it always grows back to its Rapunzel like length. And he mentioned that she probably has a nourishing diet, likely different than mine. He was super duper nice about all of this don’t get me wrong.

My question is, can hairstyles tell if someone has an eating disorder, or if someone is malnourished??