Table 1 Illustrative Quotes Supporting Code Development and Reporting

 Variability in Weight Criteria

“…It’s someone who loses weight in an eating disordered way and the final weight they get to is not underweight by whatever standards we usually measure that. It might be very unhealthy for that person, but maybe they’re 50th percentile BMI or higher and they started out at the 90th percentile BMI.” (Par 10, pg. 2)

“So, I guess when I think about it, I’m thinking about primarily weight. So, the patient may not be significantly underweight compared to other kids their age, yet they’re underweight for their bodies and they’ve lost a significant amount of weight and they’re displaying the features of AN that we typically see in more underweight patients” (Par 11, pg. 1)

“One is the kids that, who according to their BMIs, their doctors were categorizing them as overweight, or very overweight or whatever it is and then they lose a massive amount of weight especially in a short period of time, but at the time they weren’t meeting the criteria for anorexia. So, there is sort of that category and then there’s the other kids that were caught very quickly and they just haven’t lost that much weight yet and yet they are certainly demonstrating all of the symptoms except for that extreme weight loss. Those are the two clusters that I have in mind” (Par 09, pg. 1)

 Weight is One Piece of the Medical Puzzle

“Sometimes we look at the rigidity of their thinking as well, because I find if it’s more of an atypical kind of pattern, then they are not super starved which is what you see in the anorexia and then the rigidity and thinking isn’t as strong [as typical AN]” (Par 08, pg. 2).

“I think a lot of times they are just expressing concern that the person has been not really eating as much as they used to be eating. They have noticed a lot of rigidity around food, so going to the quote on quote health food versus eating a variety of food. They have seen more irritability, signs of depression and anxiety and those types of things that they are having trouble making sense of. I think most of the time they say this is someone we have never had any problems with, she has always been really high functioning, she has always done really well for herself, and then she seems to like, her personality has really shifted.” (Par 06, pg. 2)

 Presentation of Exercise (compared to typical AN adolescents)

“Interviewer: Are they going back to exercising much more quickly?

Participant: Not necessarily. You know, when I work with these cases, the paediatrician and I guess, we decide together when a child can exercise, but it really is once they are doing much better, you know, the weight is up, there is not much resistance with eating.” (Par 19, pg. 4)

“You know, I think it’s about the same, they are…I’m just trying to think…I would say they’re about the same, I am just trying to think of the last few that we assessed and I would say that in terms of exercise being an issue, it is about the same” (Par 08, 09)

 Reintroduction of Exercise (compared to typical AN adolescents)

“Yeah, I feel like I am more lenient in my level of like my recommendations about activity. First of all, I think the family pushes it a lot – let’s find health ways to control weight – and I find that I am probably a little more lenient than with some of the other, like it seems like kind of a normal thing to do…It seems a little protective to me. Like why don’t we help them to manage some aspects of weight in a healthy way while they are still in treatment? And, I have less of a concern unless the way they lost their weight was through excessive activity…I find I feel more comfortable with them doing it while they are still in treatment and so it seems kind of more in line with the overall messaging of, ‘yes, we want to kind of promote health, but it is a healthy kind of balance of making sure you are eating enough…’ especially if they have been quite significantly overweight in the past” (Par 23, 8).

“They can’t keep doing this [exercise] no matter who they are [i.e, typical or atypical]. So the answer is not like, ‘because they have atypical AN, some level of exercise is okay in phase 1.’ No, I would never make that change” (Par 01, pg. 6)

 Weighing the Patient and Graphing the Weight Chart

“And I guess, I’m sensitive to the patient’s weight gain and their realistic fears about becoming overweight again. I think I’m more individualised about the way I present growth curves to families, whether I involve the patient in that conversation initially or not; it’s just, I don’t have one particular way of doing it, but I feel like with Atypical AN, it’s okay to sort of like deviate a little bit from the typical way of doing it” (Par 10, pg. 3)

“I show their weight curve and I talk about how you know ‘you are underweight.’ And that really confuses them a lot when I am like ‘you’re really underweight, you’re malnourished’ and they’re like, ‘I’m not underweight, I’m at the 50th percentile.’ I’m like, ‘for you, you are underweight’ and kind of showing [individual] growth curves. Parents…the curve, being able to show that data, I think helps them because sometimes it is quite dramatic.” (Par 12, pg. 9)

 Activation of the Parental Dyad and Creating an Intense Scene

“I feel like we have had these parents where we have gotten a set of instructions from the doctors about losing weight and have done everything right and have done everything that they were supposed to do and now they are being told, this isn’t okay you need to refeed them [the child]. They are just totally confused” (Par 18, pg. 1).

“I mean often times parents will, you know, notice how much the child has changed since the weight loss, and they can identify the eatingdisorder behaviours that are so atypical, or out of character, like new to the family, but I think there is less sort of identification of the eating disorder voyage as really being…you know, like sometimes with very low weight patients, like the parents are like ‘this is nuts! She still thinks she’s fat?’ and like ‘look at her!’. So, its like they can kind of identify the eating disorder as really being all the more pathological, almost like psychotic. Whereas, I think that with a patient with atypical AN, the parents maybe can understand a little bit more why the patient is concerned about their weight, you know if a patient goes from being the biggest kid in the class to maybe a little heavy, to being svelte and looking a little more like her peers, I think the parents, its maybe harder for them to understand that it’s so disordered to want to look like that…I guess yea, the parents have more empathy for the eating disorder” (Par 11, pg. 6).

 Allied Health Professionals – Disciplinary Differences

“Physicians are not really sure why the families have been referred for treatment, I feel like they see it as it conflicts with what their recommendation was and I don’t know if at times they feel like they are on the defensive like we are attacking them saying, ‘this should not have happened’ and they are saying ‘it should have happened, they [the adolescent] were overweight and they needed to lose weight.’ So I think a lot of times maybe their perception is that I am wanting to get the teen back to where they were in an overweight or obese place and I have to also give them the message that ‘no, we are not asking to re-nourish and be at an unhealthy weight, we are just wanting to make sure that we find the right balance for this teenager” (Par 22, pg. 1).

“And you know, as the therapist, you don’t want to disrespect the physician you know and sort of say ‘he doesn’t know what he is talking about’ but at the same time, you know I think sometimes I’ve had to say to parents very respectfully and very kindly that even very very good physicians don’t always get training in eating disorders and this is what we’re saying as opposed to what they’re saying and how can we all get on the same boat here?” (Par 13, pg. 5)

“They [parents and adolescents] are confused…and often, this is so sad, often these things can start from pediatricians who are well-meaning and they are saying hmmm, we need to watch your weight, maybe go on a diet, and before you know it, we have a really major health risk.” (Par 09, pg. 5).

 Determining the Goal Weight for Atypical AN Adolescents

“I’m often relying on as much behavioral evidence as I can, ‘hey this is what they’re [your child] is eating, maybe this [something different] was what they were eating before the eating disorder, and that wasn’t ideal either, however, this is what they’re doing now’ and emphasizing that this is not a phase and then what I think is compounded by all of this stuff is what’s the weight target? So, if we know that a kid needs to gain some weight, but do they need to go all the way back to where they were before? I think this is a time when often we’ll start with the 76th percentile and go up till about the 85th percentile and sort of see where we are at.” (Par 03, pg. 1).

“I do think there is a little less to guide us with these kids as far as where their weight should be so sometimes I’ll say ok, you don’t want to get her up to the 90th percentile, let’s get her up to the 75th and see how she is and I think, there’s a couple of things. One, I think it gets them [the parents] at least on board of starting the process of weight regain, but it also gives the therapist and the treatment team a little bit of wiggle room because I think it’s less clear where these kids should be.” (Par 13, pg. 13).