Background

Obesity in childhood is associated with a wide range of adverse health outcomes, both during childhood and across the life-course, including an increased risk of diabetes [1], heart disease [2] and 16 different types of cancers [3]. For those who experience obesity in childhood, their weight status often tracks into adulthood [4, 5]. The NHS cost of treating obesity and its associated illnesses reached £6.1 billion in 2014/15 and is increasing year-on-year [6]. It is therefore in the interests of both the NHS and the individual to develop innovative ways that support every patient within a weight management service.

Overweight and obesity are frequently approached with the incomplete concept of ‘eat less and move more’ [7], which could be perceived to create a calorie deficit resulting in weight loss [8]. However, this vastly underestimates the complex, biological, environmental, social and psychological drivers to eating [9, 10]. Maintaining health behaviours and sustaining weight loss requires cognitive control, motivation and self-regulation [11], particularly when the environment does not support health [10, 12]. When considering the numerous biological drivers that oppose weight loss for evolutionary survival reasons [13], including the Hypothalamic Pituitary Axis, leptin and ghrelin that work to maintain food intake and energy stores, losing weight is difficult, and maintaining weight-loss is a potentially bigger challenge [14]. Only a small percentage of people who do lose weight sustain the loss, with many regaining all they have lost [14, 15].

Children with severe obesity may be referred to a tier-three, hospital-based, multi-disciplinary team clinic [16]. The Care of Childhood Obesity clinic at Bristol Children’s hospital was used as a model to develop the new Complications related to Excess Weight clinics, which will go some way to addressing inequalities of access [17]. These clinics treat patients experiencing complex and enduring obesity, with a body mass index (BMI) above the 99.6% percentile for age and sex, and health conditions resultant from excess weight., Patients seen at the clinic are treated using lifestyle guidance, dietetic programmes and psychological support, from a multi-disciplinary team. Following assessment of the severity of obesity in presenting patients, the clinic can utilise diagnostic and genomic testing, pharmaco-therapy and bariatric surgery.

However, the two reviews of the clinic to date acknowledged that the approaches used did not suit everyone. Younger patients without a family history of obesity [18] and with the advantage of motivated and more resourced families, are most likely to benefit from the clinic’s approach [19]. For the year 2021/22, 46% of patients were not supported by the clinic to improve their adiposity and this patient group was found to have complex obesity, with related behavioural or social issues including autism spectrum disorder, attention deficit hyperactivity disorder or socioeconomic deprivation. These patients may drop out of the clinic or may continue to attend but without achieving the desired outcomes [18].

To support long-term success, the implementation of evidence-based behaviour change strategies are recommended [20]. An understanding of the complex and numerous factors that cause and maintain obesity can be used to implement targeted behaviour change [21]. To be effective, the development of the intervention should be theory-led and grounded in behavioural science, but also incorporate the patient perspective [16, 20]. Such integrated approaches to intervention design have been shown to offer enhanced clarity of intervention focus and ability to meet patient needs [22].

The objective of this research is to develop a feasible, effective intervention tailored for those young people who do not experience progress in a tier-three weight management service. Here, we present the first three stages of this process: (1) intervention planning, (2) intervention development and (3) testing the concept. This intervention was initially planned and designed at the Bristol Care of Childhood Obesity clinic, with the view to trialling the intervention in the Complication from Excess Weight NHS clinics [17]. Thus, the scalability and deliverability of the intervention across sites providing broad geographic and demographic reach has been considered in this context.

Approach

To select frameworks of behaviour change, a recent systematic review of behavioural intervention development tools was consulted [20]. Methods from (i) the person-based approach [23] facilitating a focus on patient acceptability and feasibility, and (ii) a theory and evidence-based approach (the COM-B [24]), were brought together for intervention development. The stages were conducted in an iterative manner, with each step informing the next. The intervention planning stage included re-analysis of existing data through qualitative methods. The intervention development stage included the design of the intervention using the COM-B framework and the development of guiding principles [23]. Importantly, patient and public involvement (PPI) groups were then consulted to ensure the intervention met the needs of the population.

To ensure lived experience remains the primary focus of our intervention design, a member of the PPI group, with lived experience of obesity (GT), was invited to join the research team as a PPI representative. Her contributions iteratively feed into each stage of the development.

Stage 1: Intervention planning

Qualitative methods

Rationale

Understanding the population for whom the intervention is being designed is a fundamental first step [25]. A service review was first conducted over ten-years ago [19], and so the review was repeated in 2019 [26]. A high reliance on the support of the clinical team was found, with desire for more intensive medical involvement in the weight-loss process, with low levels of patient belief that they had the capability to sustain change themselves. Parallels with the three components of self-determination theory were drawn, as the patients did not demonstrate fulfilment of relatedness (feeling supported), autonomy (empowered to make their own choices), or a sense of competency (feel able to make changes) [27,28,29]. Without self-determination, which includes being attuned with our intrinsic motivations (in this case, internal reasons for weight change), weight-loss relies on external factors. Indeed, patients appeared not to utilise intrinsic motivations, meaning there is a potential for improving weight-loss outcomes if these components are increased. Evidence suggests that lifestyle changes that are intrinsically rewarding to the individual in and of themselves, are more likely to be sustained [30, 31]. The findings from the service review suggested that if self-determination can be increased in this population, it not only offers opportunity for improved weight-management outcomes but also facilitates improved self-management skills that can be transferable throughout the young person's life. The rich qualitative data in the study [26] provided the opportunity for re-analysis from an intervention planning perspective that is presented here.

Qualitative research process

Semi-structured interviews were conducted with twelve families who attended the Care of Childhood Obesity clinic [26]. The interviews were open to all service users, however all but one of those who took part were not currently seeing changes to their weight or co-morbidities following the current service approach. The views of the service user achieving weight-loss were removed from this analysis as data saturation in this area was not met. Interviews were conducted via telephone and audio recorded between January and August 2019, except one which was conducted in person. The interview data were thematically analysed following the six-step procedure of Braun & Clarke [32] by two independent and experienced qualitative researchers (JC and AS). For this intervention planning process, the transcripts were re-visited to extrapolate useful insights on the pragmatic and logistical aspects of the clinic experience, which were not focused on in the previous publication [26].

Findings

Our additional qualitative extrapolation of the interviews focussed on two themes that were framed with regard to (1) access to the clinics and the perceived support provided by clinic staff and (2) thoughts on group-based interventions provided by the clinic.

Pragmatically, the service user group were clear in reporting the difficulties of in-person attendance at this clinic, with travel, missing school and the cost being significant barriers (Table 1; Part 1). The interviews were conducted prior to the Covid-19 pandemic and the concept of online services was considered tentatively. The service users’ perspective on group work was more nuanced, with some in favour of the peer-support offered by group work and others preferring the confidentiality of one-to-one sessions due to the sensitivity that young people and peers may experience during adolescence (Table 1; Part 2).

Table 1 Additional quotes from qualitative interviews with service users and parents
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Stage 2: Intervention development

COM-B

Rationale

Whilst knowledge about the behaviours we should be increasing (e.g. activity), and those we should be decreasing (e.g. fast food consumption) is important, on its own this knowledge is rarely sufficient to create sustained change in behaviour [33]. Research into the psychology of behaviour change suggests that to be able to sustain changes, the individual needs to have the Capability, Opportunity and Motivation to perform the new Behaviour [24]. This COM-B offers a framework on which to design interventions with these key facets of behaviour change in mind [23, 34].

Approach

Using the rigorous COM-B framework for intervention design [23], an in-depth behavioural analysis was conducted to understand what needs to change before the target group (in this instance a clinical paediatric population with obesity) can change the target behaviour (in this instance, self-determination). The analysis is structured through the completion of a series of COM-B worksheets, each focussing on a different aspect to help determine how the behaviour change could be brought about. The final stages of the COM-B model guide the content and intervention implementation options and involve understanding which of 93 behaviour change techniques (BCTs), would be effective in bringing about change and via what delivery mode. Throughout, the model utilises the APEASE (Practicability, Effectiveness, Affordability, Side-effects, Equity) framework to ensure feasibility of the selected intervention. Three authors (JC, EH & AS) independently completed the COM-B process worksheets then met with clinical expert (JHS) to finalise decisions and create an overarching document (Supplementary materials).

Consideration was then given to evidence regarding the extent to which existing psychological therapies can achieve the behavioural change techniques identified from the COM-B process. Three authors (EH, AS and JC) reviewed the evidence to determine what interventions were currently being used to elicit self-determination and intrinsic motivation, in the context of weight management.

Findings

COM-B stage 1

It was apparent that an intervention to raise service users’ sense of self-determination could be successfully achieved by targeting psychological capability, social opportunity and reflective motivation or automatic motivation (Supplementary materials, Worksheet 4).

COM-B stage 2

The intervention could be effectively delivered via education, modelling, training, or enablement pathways (Supplementary materials, Worksheet 5). If the intervention were to look at changing policy, the policy categories that could be applicable were to look to influence guidelines and service provision (Supplementary materials, Worksheet 6). Based on these results, and the perspective of a clinical expert (JHS) and PPI, it was agreed that a training approach was more in-keeping with ACT’s standpoint of working alongside service users to develop collaborative solutions, rather than taking a teaching approach. It was also agreed that the clinical team modelling desired behaviours, to demonstrate how a service user could embody the behaviour change, would be an appropriate technique.

COM-B stage 3

To establish which behaviour change techniques (BCTs) were helpful to include, the BCTs were considered through the lens of increasing self-determination and were chosen based on their ability to support self-determination and intrinsic motivation. Worksheet 7a (Supplementary materials) documents all the beneficial BCTs, which include behavioural practice/rehearsal (for example practising mindfulness when feeling calm, for the skill to be more readily available in times of stress), and valued self-identity (affirming the person’s self-identity in line with the behaviour change). Furthermore, a tailored list of specific motivational BCTs (MBCTs) has been developed by expert consensus, including the authors of the COM-B model and self-determination theory. It therefore seemed pertinent to also include these MBCTs in the intervention, with items such as using empathic listening, clarifying expectations, and dealing with pressure being highly relevant (Supplementary materials, Worksheet 7b).

For clarifying modes of delivery, COM-B identified face-to-face or phone to be potential delivery options, particularly by video-call (Supplementary materials, Worksheet 8). The qualitative interviews demonstrated the difficulty patients have in accessing the clinic due to its city-centre location and the costs this incurs (Table 1), therefore we opted to run the programme via video-call.

Review of interventions to increase intrinsic motivation

While Cognitive Behavioural Therapy (CBT) is often the default in weight-management [35], there is a developing evidence base in favour of Acceptance and Commitment Therapy (ACT) [36]. ACT is a third-wave cognitive behavioural intervention, that utilises core processes that support emotional regulation, including acceptance, mindfulness, and values-based work to deepen intrinsic motivation [37]. ACT is therefore recognised as an appropriate psychological therapy for increasing self-determination [38, 39]. ACT may offer superiority to CBT in the domain of raising self-determination, due to its ability to enhance emotional self-regulation through its focus on self-awareness and mindfulness. Whilst other third-wave therapies including Mindfulness Based Cognitive Therapy and Dialectical Behavioural Therapy may also offer opportunities to raise self-determination, ACT currently demonstrates the greatest efficacy within weight management [40].

Recent reviews have considered ACT as an important approach to treating obesity in adults [11, 41,42,43,44]. Indeed, ACT has been adopted in a range of adult weight management services [42, 43], including the recent Supporting Weight Management (SWiM) trial [45]. Importantly, several iterations of ACT have been successfully developed specifically to work with young people, children, and adolescents [46, 47]. Following the above review, the present authors are now conducting a formal scoping review on the use of ACT for weight management in young people, details of which are currently available in the pre-registration (https://osf.io/523du/), and will be presented elsewhere when complete.

Guiding principles

Rationale

The development of guiding principles helps to clarify an intervention’s objectives and ensure the design meets the needs of the end user. Throughout intervention iterations, the guiding principles should be consulted to ensure the intervention retains its focus.

Approach

To develop the guiding principles, a person-based approach was utilised [24]. Together, the knowledge gained from the COM-B behavioural analysis, qualitative research study, review of the evidence and the PPI groups was considered, and overarching objectives of the intervention were agreed on by the research team. Key features of the intervention that will ensure each principle is achieved are detailed in Table 2. The development of guiding principles and key features is iterative (Fig. 1), as the intervention continues to evolve in response to PPI feedback and feasibility work with the clinical population, so it is likely that these principles will evolve too.

Table 2 Guiding principles
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Fig. 1
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Stages of intervention development

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Findings

The guiding principles (at point of publication), and the key features of the intervention that will help the principles be achieved, are detailed in Table 2.

Stage 3: Testing the concept and iterative development

Patient and Public Involvement

Rationale

To ensure the programme works for the end-user, PPI is vital throughout the intervention process.

Approach

Based on the planning and development work described above, a protocol ACT therapy manual was developed by a health psychologist trained in ACT (JC). The concepts were discussed with four PPI groups: one with young people of healthy weight and two with adults with obesity who had experienced obesity during their childhood and adolescence (some of these participants’ children were also currently experiencing obesity). The fourth group were young people with obesity who were currently engaged with a tier-3 weight management programme (Table 3).

Table 3 PPI participant details
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Findings

The feedback of the PPI group members has actively influenced both the content and the delivery of the intervention. This rich and significant feedback, and how it has been incorporated into the development process, is documented in a Table of Changes (Supplementary materials).

The PPI groups were in favour of the focus on intrinsic motivation and taking an approach of working collaboratively, with many reflecting on their own experiences of failed diet attempts when driven by external reasons, and the negative impact this pressure has had on them. Participants perceived this potential intervention as giving them a new perspective on weight management (“a new way to consider this”), whilst resonating with their own experiences (“I feel like you described my teenage years”). Changes were made to the structure of sessions (see Table of Changes, Supplementary materials), with young people now being given the option as to whether their parent, or another support figure, attends sessions with them or not. The use of the term ‘mindfulness’ was also challenged due to the term “constantly being thrown at us at school”. Overall, the group considered the approach holistic, where the therapist would seek to “build a relationship with them beyond their weight”. The transferability of the skills involved offered them “help for life”, rather than a programme that was purely about weight loss.

Discussion

Through integrating person-based insight, theory and evidence, an ACT based approach to raise self-determination in paediatric weight management has been devised. The approach will be further co-developed with young people in the Care of Childhood Obesity clinic, before a proof of concept trial is conducted within the Care of Childhood Obesity clinic and two independent Complications of Excess Weight clinics [50], with the view to incorporating this intervention into all such clinics in the future.

The integration of techniques from COM-B [23] and the person-based approach to intervention design [24], and the contribution of a PPI representative (GT) within the research team ensures lived-experience is fully integrated within this intervention design. This enables the intervention to meet current NICE guidelines, which request that all paediatric weight management interventions “have taken into account the views of children, young people and their families” [16]. Contributions from the patients and their families led the decision to take the novel approach to target self-determination and intrinsic motivation, which we perceive to be the cornerstone to life-long change. The service user perspective has also heavily influenced the logistical aspects of the intervention. The four trials that have assessed ACT use in similar young populations have also shown promising feasibility results; however, none of the interventions have been developed in a service user-led way and all have included ACT as part of an integrated weight-management intervention with multiple elements, making it difficult to delineate the effectiveness and feasibility of the ACT components in this setting [51,52,53,54]. Practical factors such as access, location and timing contribute to the high attrition typically seen within weight-management interventions [55, 56]. Consequently, the proposed intervention follows the service user lead on how and when they would like to receive the intervention, and it is hoped will yield enhanced completion rates.

The evidence suggests that ACT processes, including supporting meta-cognitive thought, clarification of values and acceptance of difficult thoughts and feelings, enhance emotional and self-regulation [11, 39]. Our PPI feedback celebrated the holistic approach to care, which offers patients a new skill set that is transferable to other elements of their lives.

Whilst CBT is the default model for clinical care, theory suggests that ACT as a third-wave CBT therapy may offer enhanced ability to generate autonomous motivation, self-regulation and sustained change [11, 43]. Potentially this is via mechanisms including emotional regulation, non-judgemental awareness, and metacognitive thought [39]. As we are creating a novel, tailored intervention in this paediatric setting, this work is a crucial step to translating theory into clinical practice.

A further intervention development process will include delivering and interactively developing the seven-week programme, session-by-session, with young people from the Care of Childhood Obesity clinic. The programme will evolve iteratively based on participants’ qualitative feedback through ‘Think aloud’ interviews to result in a programme that is tailored to meet the needs of this population. When necessary, the guiding principles will also evolve based on participant feedback, together with the evidence base including the on-going scoping review [57]. To widen the diversity of the patient voice, ensuring ethnicity is considered, further diverse and inclusive PPI advisory groups will be held with the help of mutual support group, Obesity UK. Loan devices are being made available to ensure young people from underserved communities, without the required technology, can also contribute. Once developed, the intervention will enter a proof of concept trial study, prior to a full trial to test for effectiveness within the Complications of Excess Weight clinics.

Limitations within the methodology of this development work include having a limited number of PPI advisors who were within the target age and weight-status of the intervention. We were mindful not to overload the young people who attend the Care of Childhood Obesity clinic, as they had already been involved with the service review [26], another research trial not connected to this intervention [48], and crucially will be involved with the in-depth session-by-session development phase of this intervention. Therefore, we sought alternative groups of young people with relevant lived experience to contribute to this early PPI work.

In conclusion, this development paper details the integrative approach taken to establishing ‘AIM2Change’. With further evidence, theory and patient-led research methods iteratively contributing to the final intervention, we hope to have produced an intervention that is acceptable, effective, and adhered to when rigorously trialled.