One of my most significant diagnoses is anorexia nervosa.

My T is very thin, and I noticed this right away. I think she is just a small person though, she's short too. She doesn't look unhealthy-- either too skinny or too chubby-- and I think that was very important for me.

I actually found out later that she specializes in eating disorders.

I brought her weight up with her very early on in my therapy. I think it was a positive thing. I would definitely suggest talking to your T about this issue if you can, especially if he is an ED therapist. He will understand that you are not personally insulting him. It's part of a disease and you are in therapy to get better and he should be willing to help you in any way possible.