Background Bipolar disorder is a serious mental illness, which requires new strategies for prevention and management. Recent evidence suggests that a ketogenic diet may be an effective intervention. This research aimed to explore the feasibility and acceptability of a ketogenic diet intervention for bipolar disorder, fidelity to its behavioural components and the experiences of the participants and research clinicians involved.
Methods A mixed-methods process evaluation was conducted. Semi-structured telephone interviews were carried out with 15 participants 1-2 months after completing a 6-8 week modified ketogenic diet intervention, and 4 research clinicians from the study team following the completion of data collection. Data were thematically analysed. Fidelity checklists completed by research dietitians were analysed using descriptive count and percentage statistics. Findings are reported post-hoc, following the analysis and publication of the main pilot study findings.
Results Qualitative data indicated that participants had various motives for taking part in the study, including weight loss. It was important to support people’s motives while facilitating clear and realistic expectations. Despite the challenges of initiating and maintaining a ketogenic diet, including for some its disruptive effects on daily living, many participants perceived physical and psychological benefits (e.g. significant weight loss, mood stability and an enhanced ability to focus). A range of behavioural ( e.g. goal setting), social ( e.g. family and dietitians) and technological ( e.g. apps for monitoring) support mechanisms were generally considered key facilitating factors. Meanwhile, dietary preferences, concerns about the diet and its impact, the testing burden and capacity of the delivery team were perceived as barriers for some. The importance of wider contextual influences ( e.g. the cost of living and sociocultural expectations) were highlighted. Overall, descriptive analyses indicated moderate-to-good fidelity to the behaviour change components of the study.
Conclusion We provide novel insight into the experiences of people living with bipolar disorder initiating and following a ketogenic diet, as well as those of research clinicians who support the intervention. Future trials may benefit from increased clinical research capacity, better-defined entry and exit routes, additional interpersonal support, and greater understanding of how social and societal factors impact participation.
Trial registration Study registration number: [ISRCTN6163198][1] (02 March 2022)
### Competing Interest Statement
IHC has a diagnosis of bipolar disorder and follows a ketogenic diet to manage his symptoms. His current fellowship is funded by the Baszucki Research Fund.
### Funding Statement
This study was funded by the Baszucki Brain Research Fund. BPR and SAS acknowledge funding from the UKRI Medical Research Council (MC\_UU\_00022/1) and the Chief Scientist Office of the Scottish Government Health Directorates (SPHSU16). MJT acknowledges funding from the Chief Scientist Office of the Scottish Government Health Directorates through the NHS Lothian Research and Development Office.
### Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
Ethics committee of NHS Lothian Research and Development gave ethical approval for this work.
I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.
Yes
I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).
Yes
I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.
Yes
Data generated and analysed during the current study are not publicly available as explicit consent was not sought from participants, and privacy may be compromised.
* BMI
: Body mass index
RCT
: Randomised controlled trial
SIMD
: Scottish Index of Multiple Deprivation
[1]: /external-ref?link_type=ISRCTN&access_num=ISRCTN6163198
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