Utilising a social-ecological approach to understand the barriers and facilitators of weight loss in behavioural weight management programmes

Thomson, Meigan Eilise (2023) Utilising a social-ecological approach to understand the barriers and facilitators of weight loss in behavioural weight management programmes. PhD thesis, University of Glasgow.

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Behavioural weight management programmes are efficacious in improving health and weight outcomes in adults living with obesity. Typically, a target of 5% weight loss is considered “successful” as this weight change has been associated with improvements in health. Despite the successes of these programmes, many participants fail to reach a 5% weight loss. Comparing barriers and facilitators during participation in programmes can highlight differences between those who are “successful” and “unsuccessful”. Research which aims to understand why participants are “unsuccessful” often focuses on programme or intrapersonal factors and does not consider wider contextual and environmental influences on experiences and outcomes. Where there is data on wider contextual influences, the data is often collected at follow-up (potentially introducing hindsight bias) or fails to compare commonalities and differences between “successful” and “unsuccessful” participants. Gathering data on what factors (i.e. internal, and external to the programme) influence success during participation can provide suggestions on how programmes can be improved. Therefore, this research aimed to explore the barriers and facilitators of weight loss for participants in behavioural weight management programmes, and to compare commonalities and differences between “successful” and “unsuccessful” participants, using a social-ecological approach.
The study used a two-phase convergent parallel design mixed methods approach. This involved collecting qualitative and quantitative data concurrently, analysing them independently, and then merging them for interpretation. The first phase was a systematic review of the barriers and facilitators of weight loss and participation in behavioural weight management programmes. The review used a data-based convergent synthesis to combine qualitative and quantitative data for thematic analysis. Quality assessments were used to rank the trustworthiness of the themes identified in the data. The second phase involved a combination of surveys, interviews and personal network data collection with adults living with obesity participating in a 12-week online behavioural weight management programme. The content of the surveys and interviews was informed by the wider literature and systematic review and asked participants the degree to which and how different aspects described in the social-ecological model impacted their weight loss. Questions included intrapersonal, interpersonal, programme, environment, and also COVID-19 topics. Surveys were administered at baseline (n= 129) and the end of the programme (n= 102). Survey data were analysed using a sequential modelling approach to build an explanatory model of “successful” weight loss (i.e. ≥5%). Semi-structured interviews (n=48) were conducted midway through the programme. Data were analysed using a thematic framework approach. The data were coded before participants were grouped as “successful” or “unsuccessful” at achieving a ≥5% weight loss. Following the coding and grouping of participants, the themes were compared to identify commonalities and differences in the barriers and facilitators experienced between groups. Personal network data were collected at each timepoint as part of the surveys or interviews. Personal networks required participants to nominate people they spend time with (i.e. an alter) and answer questions on their attributes and connections to other alters. The personal network data explored the structure of participant networks (e.g. number of alters, density) and characteristics of the alters (e.g. their weight status, whether they offered social support) in the participants' lives and whether they affected success.
Following individual analysis of each study, the results were combined into a conceptual map to reveal a comprehensive overview of influential factors of “successful” weight loss. Factors which were identified in each study were then extracted to highlight key contributors to success.
The systematic review identified 48 studies, including qualitative, randomised controlled trials and quasi-experimental methodologies. In total 39 barriers and 40 facilitators were extracted. Due to the generally high quality of the included studies, most themes were ranked as having high trustworthiness. Important factors included intrapersonal thoughts, feelings, behaviours and health, interpersonal dynamics, the programme materials, setting, and being mindful of participants and the facilities in the wider environment. The survey also identified a range of key influential factors across social-ecological domains. The explanatory model found lower baseline takeaway consumption, more dietary changes made at baseline and the end of the programme, lower levels of anxiety, and higher levels of social support from the household accounted for 29% of the variance in whether participants would successfully reach a 5% weight loss.
The thematic framework analysis of the interview data revealed commonalities and distinctions between “successful” and “unsuccessful” participants. Commonalities largely reiterated the themes in the systematic review. Factors only reported by “successful” participants included being motivated by stressors, sourcing pragmatic solutions to barriers, being proactive in learning about risks associated with excess bodyweight and being aware of negative media and public health messaging concerning obesity. Factors only reported by “unsuccessful” participants included having challenging work patterns, disliking their weight target, having difficulty in managing stressors and overcoming barriers, being resistant to social support, and experiencing negative social reactions to their weight managements attempts.
The personal network data collected as part of the surveys offered limited insights into the relationship between the network and weight loss due to issues with the data collection methods. The personal networks collected in the interviews did not find any significant relationships between “successful” weight loss and any of the tested variables.
The integration of the results from the systematic review, surveys, and interviews highlighted intrapersonal and interpersonal factors as important contributors to “successful” weight loss. These included the adoption of more behavioural changes, receiving higher levels of social support, having higher levels of motivation, self-efficacy, and control, and lower levels of anxiety and depression.
This research identified crucial barriers and facilitators for “successful” weight loss in adults living with obesity participating in behavioural weight management programmes. The findings show there are a variety of influential factors across the social-ecological model, and the importance and effect of these vary between participants. Although it’s not feasible to address all challenges, programmes can use these results to harness the best conditions for success within their control (e.g. adding in extra programme components, and considering how to address external challenges). Based on the findings from each study, suggestions for practice, policy and research are offered.

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Additional Information: Grant reference number: MC_ST_U18004
Colleges/Schools: College of Medical Veterinary and Life Sciences > School of Health & Wellbeing > MRC/CSO Unit
Supervisor's Name: Simpson, Prof. Sharon, Martin, Dr. Anne, Long, Dr. Emily and Logue, Prof. Jennifer
Date of Award: 2023
Depositing User: Theses Team
Unique ID: glathesis:2023-83511
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 29 Mar 2023 10:29
Last Modified: 30 Mar 2023 11:27
Thesis DOI: 10.5525/gla.thesis.83511
URI: https://theses.gla.ac.uk/id/eprint/83511
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