Like with most ED's, the cause of your ED is most likely tied to the cause of your PTSD. when the stresses in my life flaired up, so did my ED. Treatment mostly tries to get the ED under control without working on the REAL underlying cause.

My GP while he had me in the medical hospital on & off for 2 months ran every medical test to prove it wasn't physical but no one bothered to help me deal with the trauma I was going through that was the REAL trigger for the anorexia at that final point I was so sick.

Everything is so tied together in our bodies between emotional & physical & most of the time our ED issues don't start off because of body image but turn into that with weight loss that becomes addictive. The real triggers however are things long before that point....the things that created the stress in our life in the first place. Yes, treatment providers find it easier to only look at the surface issues because the REAL depth of the problem is so complex & so individual, their only concern is getting the person to eat at that point in time so they survive. never got to the heart of the issue. For me I didn't get to the heart of my first time with anorexia in 1995 until just a few years ago around 2015 even after going through the second time I knew was triggered by the trauma.

Dealing with your PTSD will give you huge insight into your SH & your ED so keep focusing on that & continue allowing your nutritionist to help with accountability with your eating to try to keep as stable as possible during flair ups due to things treatment brings up