Table 3.

Adulthood themes

Themes	Examples
1. Management of PKU	I like the liberty of having a normal cookie or biscuit every now and again. (Participant 6)
2. The unique experience of having PKU
2a. Eating in a social context	…when they [restaurants] make salads, some of the salads, like Caesar salads or something, has cheese in it and say could you not have cheese, and they look at you like you’re weird… I just feel different… it always brings your mood down. (Participant 1) …But it’s just so hard, like even when you’re happy, you go out for tea and, you could just imagine if you were on the diet, then what would you eat? You know, places like that don’t exactly have menus for PKU people, do they? (Participant 1) …so really socially, it’s probably been an impact and going to parties and things like that. Having functions on where umm… I almost have to eat before I go, I can’t eat there. (Participant 7) It’s normally fine… I try not to eat tons of protein during the day, so I can have like a bowl of pasta or things like that… I really like Asian food and Indian food which is great because it’s just easy to get a pure vegetable dish. (Participant 3)
2b. Effects of dietary compliance	…when my levels get higher umm… obviously the mood swings umm you feel, you get like, you feel sort of a little bit lethargic and you don’t really want to do anything and you, it takes a while to umm to process stuff and just, my thinking’s just probably a little bit slower… (Participant 5) I can feel it. I just go, oh I feel like my brain’s all fuzzy and I can’t think straight. (Participant 6). … having depression as well and not being on diet really is a bad combination. (Participant 1) So everything was just so much better. And mood swings were probably better too… huge change just in how I handled day-to-day things with stress and stuff like that. (Participant 7)
2c. Transition from childhood to adulthood management of the condition	…like counting out properly and that type of stuff, yeah… she [her mother] used to make a lot of food for me, so she did it all, so umm… yeah I didn’t really do it myself, kind of thing. (Participant 8)
2d. Attitudes and perceptions	I don’t really worry about it, I don’t think about it…I’ve had it my whole life, it’s who I am, you know. (Participant 2) You know, it’s just kind of been part of my life so I’ve just dealt with it and I just know exactly what I can eat and I can’t eat and how much of, you know, something I can eat and that kind of thing. (Participant 3) …oh my god, this is so hard, I’ve gotta weigh everything, I can’t go out, I can’t do this, I have to take my own food with me, so it is a big, it is a big stress… (Participant 7) … your life revolves around your diet… you always think about what you’re going to be eating. (Participant 6)
3. Psychological wellbeing	…my eating was umm… a problem for me… so I think it [PKU] might have been a part of it. Like it was all, like cuz I wasn’t allowed. I didn’t have a choice, I wasn’t allowed to… (Participant with previous eating disorder) …you need to be working on both things at the same time. So getting back on diet and look after yourself, after your mental health, is two things that need to happen together. (Participant 1)