Most mental health clinicians learn how to treat the most common illnesses such as depression and anxiety. Certain psychiatric problems are not addressed in standard training, so finding specifically trained therapists and doctors is important.
Eating disorders turn out to be among the most specialized example.
The majority of training for psychiatrists, psychologists and social workers does not address how to treat people with eating disorders except in the most cursory ways. And eating disorders have the most medical complications of any mental illness, a fact which demands an added level of expertise.
Clinicians need to be able to differentiate between the medical effects of binging, purging and starvation and the psychological effects of an eating disorder itself. They need to learn when to seek not only psychiatric help but medical help and work together closely on a team that attends to chronic medical issues. They need to understand the different levels of care available to patients, not only to choose between them but to understand if these options are even appropriate.
Even more importantly, clinicians need to be aware that eating disorders cause severe medical problems and have the highest rate of death of all mental illnesses. Leaving one's fate to a minimally trained clinician seems foolhardy.
It's best for patients to seek clinicians who claim expertise and significant experience treating people with eating disorders and then to ask in more detail about that experience and about possible treatment plans. The answers to those questions can give a lot of information quickly.
Also finding a primary therapist with experience is likely to open treatment up to a team of clinicians who can start one's path to recovery. Wasting time seeking help from people with limited experience will only extend the time of suffering.