The first appointment will likely be a 'getting-to-know-you' session, a detailed history, figuring out how 'your' ED affects you, what you feel you can and cannot tackle. They will ask whether why can weight and measure you to get an up to date BMI but will not insists if that is too much for you. They may ask for more blood tests (ED bloods look for more micronutrients that what you'd normally worry about in somebody who is eating/not purging), they may look at things like body hair (on your arms for instance) and skin fold thickness (again, usually arms - it is a measure of body fat which is so important for us).
ED clinician may be a nurse - most ED teams are multidisciplinary (specialist nurses and doctors, OTs, psychologist, dieticians etc etc).
I am sure what exactly happens will vary from team to team, but the main purpose of the first meeting is to get to know each other and to hopefully enable you to engage with follow up and whatever help they can offer.
The rational side of me accepts this is a very good service, and I have so far been treated very well and at speed. The irrational, unwell side is in a complete panic.
I think that is a really interesting statement and so true of so many people with EDs: you know that what you are doing is not good for you or 'normal', but threatening that safety blanket, that bit of control that your ED give you is really, really scary.
Which is why addressing it is a very brave thing to do, so kudos to you 