Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for the opportunity to review this manuscript. The authors present a qualitative enquiry understanding barriers and facilitators as well as solutions to increase PA/E in individuals with PKU. The sample has an impressive sample size and has used some appropriate processes to support rigour. I have a few comments and suggestions to help improve the clarify of the manuscript:

• Terminology – The use of the term “nutrition” throughout was confusing (i.e. explore the barriers, facilitators and solutions to participation in PA/E, sport, and nutrition) because the research questions is focused on PA/E. Nutrition does not appear to be an individual concept for exploration. Consider the use of this term particularly in intro, methods and discussion. I acknowledge that participants may have discussed this in results.
• Were the FGs recorded? Who transcribed these?
• Was there any coding done by other members of the research team? 
• What industries where the industry representatives from? E.g. pharmaceutical/medical nutrition therapy? Or did this include professional body representatives?
• Curious to understand more about why this research has a positivist approach. Are you seeking an objective truth? Or is it more of an interpretivist approach? See this paper on internal coherence in research: https://pmc.ncbi.nlm.nih.gov/articles/PMC8361966/#ndi12680-sec-0008
• The extensive quotes do demonstrate the richness of discussion, but I don’t think all are required as there is some repetition, particularly in Table 3. I would suggest one key quote from each different stakeholder. Additional quotes could be moved to supplementary material.
• Similarly, the manuscript is very long. Suggest reducing the results text, focusing on minimising repletion of quotes. Also, suggest minimising repetition in the discussion also.
• Regarding solutions, it would be helpful to have a consolidated list of solutions mapped to main themes i.e. brief dot points that summarise each solution. E.g. increased sporting opportunities within local communities, PKU events, clubs or activities school. This could be integrated into Table 3 as an additional column.
• “Several clinicians and industry representatives did not think PA/E or sport would be physically more challenging for those with PKU compared with the general population.” I did not find this particularly clear in the data. Could this and other conflicts be indicated somehow in Tables 2 and 3?

Author Response

Please see attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you very much for the manuscript. In my opinion, the topic is highly relevant. Exercise is very important for general health and weight control, also for patients with PKU. In our experience, adult patients often suffer from overweight and obesity.  Patients' attempts to lose weight often come at the expense of metabolic control. This must be prevented. Encouaging patients for healty food choice and regular physical activity can help to prevent overweight and obesity.

It is therefore important to identify barriers to exercise and find appropriate solutions. I recommend accepting the manuscript for publication. However, minor revisions should be made first. 

1)    I believe the manuscript would benefit from being shortened, especially the introduction. 
2)    Is it possible to provide some information about the participating patients? (Are they all on a diet? Are patients in the group perhaps following a relaxed diet due to adjuvant BH4 therapy? Are the patients physically active?)

Author Response

Please see attachment.

Author Response File: Author Response.pdf