Young children's choices and thoughts about pro-social behaviour towards others with overweight.

OBJECTIVES: This study aimed to investigate weight bias within young children's pro-social choices between characters who differed in body size. METHODS: Seventy-six children aged 4-6 years read stories asking them to choose who they would first help, share with, comfort, and steal from, between a healthy weight and child with overweight. They also selected the one character they would most like to play with. Children's reasoning for these choices was recorded and analysed. RESULTS: The character with overweight was helped first in only a third of the choices made. Children chose the characters with overweight more often as the target for anti-social action. In friendship selections, children overwhelmingly rejected the characters with overweight. However, weight bias was not prominent in the reasons children gave for the choices. Most children were not negative about body shape, weight or appearance. Similarly, in friendship choices, these were mostly expressed positively to the character chosen. Only a small minority of children were explicitly negative about the character with overweight. CONCLUSIONS: A better understanding of weight bias acquisition and variation between children will benefit those working in health care and educational settings. Future research should link with developmental theory, such as on social categorization and theory of mind.

Multiplex single-cell chemical genomics reveals the kinase dependence of the response to targeted therapy.

Chemical genetic screens are a powerful tool for exploring how cancer cells' response to drugs is shaped by their mutations, yet they lack a molecular view of the contribution of individual genes to the response to exposure. Here, we present sci-Plex-Gene-by-Environment (sci-Plex-GxE), a platform for combined single-cell genetic and chemical screening at scale. We highlight the advantages of large-scale, unbiased screening by defining the contribution of each of 522 human kinases to the response of glioblastoma to different drugs designed to abrogate signaling from the receptor tyrosine kinase pathway. In total, we probed 14,121 gene-by-environment combinations across 1,052,205 single-cell transcriptomes. We identify an expression signature characteristic of compensatory adaptive signaling regulated in a MEK/MAPK-dependent manner. Further analyses aimed at preventing adaptation revealed promising combination therapies, including dual MEK and CDC7/CDK9 or nuclear factor κB (NF-κB) inhibitors, as potent means of preventing transcriptional adaptation of glioblastoma to targeted therapy.

Can the delivery of behavioural support be improved in the NHS England Low-Calorie Diet Programme? An observational study of behaviour change techniques.

BACKGROUND: Previous research has illustrated a drift in the fidelity of behaviour change techniques (BCTs) during the design of the pilot NHS England Low-Calorie Diet (NHS-LCD) Programme. This study evaluated a subsequent domain of fidelity, intervention delivery. Two research questions were addressed: (1) To what extent were BCTs delivered with fidelity to providers programme plans? (2) What were the observed barriers and facilitators to delivery? METHODS: A mixed-methods sequential explanatory design was employed. Remote delivery of one-to-one and group-based programmes were observed. A BCT checklist was developed using the BCT Taxonomy v1; BCTs were coded as present, partially delivered, or absent during live sessions. Relational content analysis of field notes identified observed barriers and facilitators to fidelity. RESULTS: Observations of 122 sessions across eight samples and two service providers were completed. Delivery of the complete NHS-LCD was observed for five samples. Fidelity ranged from 33% to 70% across samples and was higher for group-based delivery models (64%) compared with one-to-one models (46%). Barriers and facilitators included alignment with the programme's target behaviours and outcomes, session content, time availability and management, group-based remote delivery, and deviation from the session plan. CONCLUSIONS: Overall, BCTs were delivered with low-to-moderate fidelity. Findings indicate a dilution in fidelity during the delivery of the NHS-LCD and variation in the fidelity of programmes delivered across England. Staff training could provide opportunities to practice the delivery of BCTs. Programme-level changes such as structured activities supported by participant materials and with sufficient allocated time, might improve the delivery of BCTs targeting self-regulation.

Physician-patient race-match reduces patient mortality.

This paper assesses the impacts of physician-patient race-match, especially Black patients paired with Black physicians, on patient mortality. We draw on administrative data from Florida, linking hospital encounters from mid-2011 through 2014 to information from the Florida Physician Workforce Survey. Focusing on uninsured patients experiencing unscheduled hospital admissions who are conditionally randomly assigned to physicians, we find that physician-patient race-match for Black patients reduces the likelihood of within-hospital mortality by 0.28 percentage points, a 27 % reduction relative to the overall mortality rate. An alternative identification strategy relying on instrumental variables provides a similar finding.

Multiplex single-cell chemical genomics reveals the kinase dependence of the response to targeted therapy.

Chemical genetic screens are a powerful tool for exploring how cancer cells' response to drugs is shaped by their mutations, yet they lack a molecular view of the contribution of individual genes to the response to exposure. Here, we present sci-Plex-Gene-by-Environment (sci-Plex-GxE), a platform for combined single-cell genetic and chemical screening at scale. We highlight the advantages of large-scale, unbiased screening by defining the contribution of each of 522 human kinases to the response of glioblastoma to different drugs designed to abrogate signaling from the receptor tyrosine kinase pathway. In total, we probed 14,121 gene-by-environment combinations across 1,052,205 single-cell transcriptomes. We identify an expression signature characteristic of compensatory adaptive signaling regulated in a MEK/MAPK-dependent manner. Further analyses aimed at preventing adaptation revealed promising combination therapies, including dual MEK and CDC7/CDK9 or NF-kB inhibitors, as potent means of preventing transcriptional adaptation of glioblastoma to targeted therapy.

Eating disorders in weight-related therapy (EDIT): Protocol for a systematic review with individual participant data meta-analysis of eating disorder risk in behavioural weight management.

The Eating Disorders In weight-related Therapy (EDIT) Collaboration brings together data from randomised controlled trials of behavioural weight management interventions to identify individual participant risk factors and intervention strategies that contribute to eating disorder risk. We present a protocol for a systematic review and individual participant data (IPD) meta-analysis which aims to identify participants at risk of developing eating disorders, or related symptoms, during or after weight management interventions conducted in adolescents or adults with overweight or obesity. We systematically searched four databases up to March 2022 and clinical trials registries to May 2022 to identify randomised controlled trials of weight management interventions conducted in adolescents or adults with overweight or obesity that measured eating disorder risk at pre- and post-intervention or follow-up. Authors from eligible trials have been invited to share their deidentified IPD. Two IPD meta-analyses will be conducted. The first IPD meta-analysis aims to examine participant level factors associated with a change in eating disorder scores during and following a weight management intervention. To do this we will examine baseline variables that predict change in eating disorder risk within intervention arms. The second IPD meta-analysis aims to assess whether there are participant level factors that predict whether participation in an intervention is more or less likely than no intervention to lead to a change in eating disorder risk. To do this, we will examine if there are differences in predictors of eating disorder risk between intervention and no-treatment control arms. The primary outcome will be a standardised mean difference in global eating disorder score from baseline to immediately post-intervention and at 6- and 12- months follow-up. Identifying participant level risk factors predicting eating disorder risk will inform screening and monitoring protocols to allow early identification and intervention for those at risk.

Child and adolescent obesity.

The prevalence of child and adolescent obesity has plateaued at high levels in most high-income countries and is increasing in many low-income and middle-income countries. Obesity arises when a mix of genetic and epigenetic factors, behavioural risk patterns and broader environmental and sociocultural influences affect the two body weight regulation systems: energy homeostasis, including leptin and gastrointestinal tract signals, operating predominantly at an unconscious level, and cognitive-emotional control that is regulated by higher brain centres, operating at a conscious level. Health-related quality of life is reduced in those with obesity. Comorbidities of obesity, including type 2 diabetes mellitus, fatty liver disease and depression, are more likely in adolescents and in those with severe obesity. Treatment incorporates a respectful, stigma-free and family-based approach involving multiple components, and addresses dietary, physical activity, sedentary and sleep behaviours. In adolescents in particular, adjunctive therapies can be valuable, such as more intensive dietary therapies, pharmacotherapy and bariatric surgery. Prevention of obesity requires a whole-system approach and joined-up policy initiatives across government departments. Development and implementation of interventions to prevent paediatric obesity in children should focus on interventions that are feasible, effective and likely to reduce gaps in health inequalities.

Improving programme-led and focused interventions for eating disorders: An experts' consensus statement-A UK perspective.

OBJECTIVE: Eating disorders are associated with significant illness burden and costs, yet access to evidence-based care is limited. Greater use of programme-led and focused interventions that are less resource-intensive might be part of the solution to this demand-capacity mismatch. METHOD: In October 2022, a group of predominantly UK-based clinical and academic researchers, charity representatives and people with lived experience convened to consider ways to improve access to, and efficacy of, programme-led and focused interventions for eating disorders in an attempt to bridge the demand-capacity gap. RESULTS: Several key recommendations were made across areas of research, policy, and practice. Of particular importance is the view that programme-led and focused interventions are suitable for a range of different eating disorder presentations across all ages, providing medical and psychiatric risk are closely monitored. The terminology used for these interventions should be carefully considered, so as not to imply that the treatment is suboptimal. CONCLUSIONS: Programme-led and focused interventions are a viable option to close the demand-capacity gap for eating disorder treatment and are particularly needed for children and young people. Work is urgently needed across sectors to evaluate and implement such interventions as a clinical and research priority.

Identifying Factors Which Influence Eating Disorder Risk during Behavioral Weight Management: A Consensus Study.

This study aimed to understand clinician, researcher and consumer views regarding factors which influence eating disorder (ED) risk during behavioral weight management, including individual risk factors, intervention strategies and delivery features. Eighty-seven participants were recruited internationally through professional and consumer organizations and social media and completed an online survey. Individual characteristics, intervention strategies (5-point scale) and delivery features (important/unimportant/unsure) were rated. Participants were mostly women (n = 81), aged 35-49 y, from Australia or United States, were clinicians and/or reported lived experience of overweight/obesity and/or ED. There was agreement (64% to 99%) that individual characteristics were relevant to ED risk, with history of ED, weight-based teasing/stigma and weight bias internalization having the highest agreement. Intervention strategies most frequently rated as likely to increase ED risk included those with a focus on weight, prescription (structured diets, exercise plans) and monitoring strategies, e.g., calorie counting. Strategies most frequently rated as likely to decrease ED risk included having a health focus, flexibility and inclusion of psychosocial support. Delivery features considered most important were who delivered the intervention (profession, qualifications) and support (frequency, duration). Findings will inform future research to quantitatively assess which of these factors predict eating disorder risk, to inform screening and monitoring protocols.

A Qualitative Process Evaluation of Participant Experiences in a Feasibility Randomised Controlled Trial to Reduce Indulgent Foods and Beverages.

There is a growing interest in the effects of ultra-processed/energy-dense nutrient-poor foods on health outcomes, and few interventions to reduce their consumption have been tested. We tested a simple intervention to help people reduce the indulgences they consume (energy-dense nutrient-poor (EDNP) foods). Herein, we report the qualitative findings to understand how participants reduced their consumption by exploring intervention fidelity and the factors affecting consumption. We conducted a qualitative descriptive study of 23 adults who had taken part in a feasibility randomised controlled trial that asked participants to say no to seven indulgences/week and record what they said no to. Data were collected using face-to-face semi-structured interviews and analysed thematically. A total of 23 adults with an average BMI of 30.8 kg/m2 took part. Participants liked the term indulgence, as they could apply it to their normal dietary intake and make small changes. They found self-monitoring what they said no to helpful and reported that emotional eating and habits affected consumption. They had difficulty overcoming these. As most people are consuming too many foods that are EDNP, this simple intervention of "Say No" seven times/week has the potential to be developed as a public health campaign.

Eating disorder risk during behavioral weight management in adults with overweight or obesity: A systematic review with meta-analysis.

This systematic review examined change in eating disorder risk during weight management interventions. Four databases and clinical trials registries were searched in March and May 2022, respectively, to identify behavioral weight management intervention trials in adults with overweight/obesity measuring eating disorder symptoms at pre- and post-intervention or follow-up. Random effects meta-analyses were conducted examining within group change in risk. Of 12,023 screened, 49 were eligible (n = 6337, mean age range 22.1 to 59.9 years, mean (SD) 81(20.4)% female). Interventions ranged from 4 weeks to 18 months, with follow-up of 10 weeks to 36 months post-intervention. There was a within group reduction in global eating disorder scores (20 intervention arms; Hedges' g = -0.27; 95% CI -0.36, -0.17; I2 67.1%) and binge eating (49 intervention arms; -0.66; 95% CI -0.76, -0.56; I2 82.7%) post-intervention, both maintained at follow-up. Of 14 studies reporting prevalence or episodes of binge eating, all reported a reduction. Four studies reported eating disorder symptoms, not present at baseline, in a subset of participants (0%-6.5%). Overall, behavioral weight management interventions do not increase eating disorder symptoms for most adults; indeed, a modest reduction is seen post-intervention and follow-up. A small subset of participants may experience disordered eating; therefore, monitoring for the emergence of symptoms is important.

Eating Disorders In weight-related Therapy (EDIT) Collaboration: rationale and study design.

The cornerstone of obesity treatment is behavioural weight management, resulting in significant improvements in cardio-metabolic and psychosocial health. However, there is ongoing concern that dietary interventions used for weight management may precipitate the development of eating disorders. Systematic reviews demonstrate that, while for most participants medically supervised obesity treatment improves risk scores related to eating disorders, a subset of people who undergo obesity treatment may have poor outcomes for eating disorders. This review summarises the background and rationale for the formation of the Eating Disorders In weight-related Therapy (EDIT) Collaboration. The EDIT Collaboration will explore the complex risk factor interactions that precede changes to eating disorder risk following weight management. In this review, we also outline the programme of work and design of studies for the EDIT Collaboration, including expected knowledge gains. The EDIT studies explore risk factors and the interactions between them using individual-level data from international weight management trials. Combining all available data on eating disorder risk from weight management trials will allow sufficient sample size to interrogate our hypothesis: that individuals undertaking weight management interventions will vary in their eating disorder risk profile, on the basis of personal characteristics and intervention strategies available to them. The collaboration includes the integration of health consumers in project development and translation. An important knowledge gain from this project is a comprehensive understanding of the impact of weight management interventions on eating disorder risk.

The need for future research into the assessment and monitoring of eating disorder risk in the context of obesity treatment.

In adolescents and adults, the co-occurrence of eating disorders and overweight or obesity is continuing to increase, and the prevalence of eating disorders is higher in people with higher weight compared to those with lower weight. People with an eating disorder with higher weight are more likely to present for weight loss than for eating disorder treatment. However, there are no clinical practice guidelines on how to screen, assess, and monitor eating disorder risk in the context of obesity treatment. In this article, we first summarize current challenges and knowledge gaps related to the identification and assessment of eating disorder risk and symptoms in people with higher weight seeking obesity treatment. Specifically, we discuss considerations relating to the validation of current self-report measures, dietary restraint, body dissatisfaction, binge eating, and how change in eating disorder risk can be measured in this setting. Second, we propose avenues for further research to guide the development and implementation of clinical and research protocols for the identification and assessment of eating disorders in people with higher weight in the context of obesity treatment. PUBLIC SIGNIFICANCE: The number of people with both eating disorders and higher weight is increasing. Currently, there is little guidance for clinicians and researchers about how to identify and monitor risk of eating disorders in people with higher weight. We present limitations of current research and suggest future avenues for research to enhance care for people living with higher weight with eating disorders.

Supporting Weight Management during COVID-19 (SWiM-C): twelve-month follow-up of a randomised controlled trial of a web-based, ACT-based, guided self-help intervention.

OBJECTIVES: We developed a guided self-help intervention (Supporting Weight Management during COVID-19, "SWiM-C") to support adults with overweight or obesity in their weight management during the COVID-19 pandemic. This parallel, two-group trial (ISRCTN12107048) evaluated the effect of SWiM-C on weight and determinants of weight management over twelve months. METHODS: Participants (≥18 years, body-mass-index ≥25 kg/m2) were randomised to the SWiM-C intervention or to a standard advice group (unblinded). Participants completed online questionnaires at baseline, four months, and twelve months. The primary outcome was change in self-reported weight from baseline to twelve months; secondary outcomes were eating behaviour (uncontrolled eating, emotional eating, cognitive restraint of food intake), experiential avoidance, depression, anxiety, stress, wellbeing and physical activity. INTERVENTIONS: SWiM-C is based on acceptance and commitment therapy (ACT). Participants had access to an online web platform with 12 weekly modules and email and telephone contact with a trained, non-specialist coach. Standard advice was a leaflet on managing weight and mood during the COVID-19 pandemic. RESULTS: 388 participants were randomised (SWiM-C: n = 192, standard advice: n = 196). The baseline-adjusted difference in weight change between SWiM-C (n = 119) and standard advice (n = 147) was -0.81 kg (95% CI: -2.24 to 0.61 kg). SWiM-C participants reported a reduction in experiential avoidance (-2.45 [scale:10-70], 95% CI: -4.75 to -0.15), uncontrolled eating (-3.36 [scale: 0-100], 95% CI: -5.66 to -1.06), and emotional eating (-4.14 [scale:0-100], 95% CI: -7.25 to -1.02) and an increase in physical activity (8.96 [MET-min/week], 95% CI: 0.29 to 17.62) compared to standard advice participants. We found no evidence of an effect on remaining outcomes. No adverse events/side effects were reported. CONCLUSIONS: Whilst we were unable to conclude that the intervention had an effect on weight, SWiM-C improved eating behaviours, experiential avoidance and physical activity. Further refinement of the intervention is necessary to ensure meaningful effects on weight prior to implementation in practice. TRIAL REGISTRATION NUMBER: ISRCTN 12107048.

Childhood Obesity and Health Care Utilization: Empirical Evidence from Austrian Administrative Data.

Background: Increases in pediatric obesity have been associated with higher levels of health care utilization. There is currently a lack of knowledge on the therapeutic drivers of increased health care use. Objective: To examine the association between different measures of health care utilization and BMI among children. Methods: We linked cross-sectional administrative data from a regional health insurance fund in Austria with objectively measured BMI from routine school health examinations in 6-15-year-old children (n = 13,493). Differences in probabilities of annual health care utilization (drug prescriptions by therapeutic classification, physician visits by medical specialty, and hospitalizations) were compared between children with normal weight, overweight, or obesity using Probit regressions. Results: Children with obesity had a 1.6 and 8.6 percentage points (pp) higher probability of outpatient doctor visits and prescribed medication, respectively (all p < 0.05). Children with overweight were intermediate. There was a higher probability of consulting a general practitioner, pediatrician, or orthopedist, and higher levels of prescribing for children with obesity across most common drug groups. Children with obesity were ∼40% more likely to receive medication for musculoskeletal and for mental health problems. This was reflected in orthopedic clinic appointments but not in psychology clinics. There were no major differences by gender or age, or parental socioeconomic status. Conclusions: Our data show clear and objective evidence of higher health care utilization by children with obesity. This highlights the importance of policy interventions to curb obesity in children and young people.

Effectiveness and cost-effectiveness of referral to a commercial open group behavioural weight management programme in adults with overweight and obesity: 5-year follow-up of the WRAP randomised controlled trial.

BACKGROUND: There is evidence that commercially available behavioural weight management programmes can lead to short-term weight loss and reductions in glycaemia. Here, we aimed to provide the 5-year impact and cost-effectiveness of these interventions compared with a brief intervention. METHODS: WRAP was a non-blinded, parallel-group randomised controlled trial (RCT). We recruited from primary care practices in England and randomly assigned participants to one of three interventions (brief intervention, 12-week open-group behavioural programme [WW, formerly Weight Watchers], or a 52-week open-group WW behavioural programme) in an uneven (2:5:5) allocation. Participants were followed up 5 years after randomisation using data from measurement visits at primary care practices or a research centre, review of primary care electronic medical notes, and self-report questionnaires. The primary outcome was change in weight at 5 years follow-up, assessed using analysis of covariance. We also estimated cost-effectiveness of the intervention. This study is registered at Current Controlled Trials, ISRCTN64986150. FINDINGS: Between Oct 18, 2012, and Feb 10, 2014, we recruited 1269 eligible participants (two participants were randomly assigned but not eligible and therefore excluded) and 1040 (82%) consented to be approached about additional follow-up and to have their medical notes reviewed at 5 years. The primary outcome (weight) was ascertained for 871 (69%) of 1267 eligible participants. Mean duration of follow-up was 5·1 (SD 0·3) years. Mean weight change from baseline to 5 years was -0·46 (SD 8·31) kg in the brief intervention group, -1·95 (9·55) kg in the 12-week programme group, and -2·67 (9·81) kg in the 52-week programme. The adjusted difference in weight change was -1·76 (95% CI -3·68 to 0·17) kg between the 52-week programme and the brief intervention; -0·80 (-2·13 to 0·54) kg between the 52-week and the 12-week programme; and -0·96 (-2·90 to 0·97) kg between the 12-week programme and the brief intervention. During the trial, the 12-week programme incurred the lowest cost and produced the highest quality-adjusted life-years (QALY). Simulations beyond 5 years suggested that the 52-week programme would deliver the highest QALYs at the lowest cost and would be the most cost-effective. No participants reported adverse events related to the intervention. INTERPRETATION: Although the difference in weight change between groups was not statistically significant, some weight loss was maintained at 5 years after an open-group behavioural weight management programme. Health economic modelling suggests that this could have important implications to reduce the incidence of weight-related disease and these interventions might be cost-saving. FUNDING: The UK National Institute for Health and Care Research Programme Grants for Applied Research and the Medical Research Council.

How is the NHS Low-Calorie Diet Programme expected to produce behavioural change to support diabetes remission: An examination of underpinning theory.

Background: In 2020, the National Health Service Low-Calorie Diet Programme (NHS-LCD) was launched, piloting a total diet (TDR) replacement intervention with behaviour change support for people living with Type 2 Diabetes (T2D) and excess weight. Four independent service providers were commissioned to design and deliver theoretically grounded programmes in localities across England. Aims: 1) to develop a logic model detailing how the NHS-LCD programme is expected to produce changes in health behaviour, and (2) to analyse and evaluate the use of behaviour change theory in providers' NHS-LCD Programme designs. Methods: A documentary review was conducted. Information was extracted from the NHS-LCD service specification documents on how the programme expected to produce outcomes. The Theory Coding Scheme (TCS) was used to analyse theory use in providers' programme design documents. Results: The NHS-LCD logic model included techniques aimed at enhancing positive outcome expectations of programme participation and beliefs about social approval of behaviour change, to facilitate programme uptake and behaviour change intentions. This was followed by techniques aimed at shaping knowledge and enhancing the ability of participants to self-regulate their health behaviours, alongside a supportive social environment and person-centred approach.Application and type of behaviour change theory within service providers' programme designs varied. One provider explicitly linked theory to programme content; two providers linked 63% and 70% of intervention techniques to theory; and there was limited underpinning theory identified in the programme design documents for one of the providers. Conclusion: The nature and extent of theory use underpinning the NHS-LCD varied greatly amongst service providers, with some but not all intervention techniques explicitly linked to theory. How this relates to outcomes across providers should be evaluated. It is recommended that explicit theory use in programme design and evidence of its implementation becomes a requirement of future NHS commissioning processes.

Participants' experiences of mental health during a COVID-19 tailored ACT-based behavioural weight management intervention: a qualitative study.

PURPOSE: We aimed to explore participants' experiences of mental health during an acceptance and commitment therapy (ACT)-based guided self-help intervention to support weight management in adults with overweight or obesity during the COVID-19 pandemic (SWiM-C: Supporting Weight Management during COVID-19). METHODS: We conducted semi-structured telephone interviews with twenty participants and used reflexive thematic analysis to identify patterns of meaning across the dataset relevant to mental health. RESULTS: Four themes were conceptualized: i) Mental health changes associated with SWiM-C, ii) External factors negatively impacted mental health and intervention engagement, iii) Use and impact of coping responses, and iv) Intervention preferences based on psychological needs. CONCLUSIONS: Findings suggest that participants were exposed to multiple factors, both related to and external to the intervention, that negatively impact their mental health, yet ACT-based aspects of the SWiM-C intervention appeared to support participants to adaptively manage the decline in their mental health. The findings can be used to inform the development of future weight management interventions, such as through intervention personalization and the inclusion of more strategies that target emotional regulation.Trial registration: ISRCTN 12107048, https://www.isrctn.com/ISRCTN12107048.

Acceptability and feasibility of an acceptance and commitment therapy-based guided self-help intervention for weight loss maintenance in adults who have previously completed a behavioural weight loss programme: the SWiM feasibility study protocol.

INTRODUCTION: The cost-effectiveness and long-term health impact of behavioural weight management programmes depends on post-treatment weight-loss maintenance. Growing evidence suggests that interventions using acceptance and commitment therapy (ACT) could improve long-term weight management. We developed an ACT-based, guided self-help intervention to support adults who have recently completed a behavioural weight loss programme. This study will assess the feasibility and acceptability of this type of intervention and findings will inform the development of a full-scale trial. METHODS AND ANALYSIS: This is a pragmatic, randomised, single-blind, parallel group, two-arm, feasibility study with an embedded process evaluation. We will recruit and randomise 60 adults who have recently completed a behavioural weight loss programme to the ACT-based intervention or standard care, using a computer-generated sequence with 2:1 allocation stratified by diabetes status and sex. Baseline and 6-month measurements will be completed using online questionnaires. Qualitative interviews will be conducted with a subsample of participants and coaches about their experiences at 3 (mid-intervention) and 6 (postintervention) months. Feasibility and acceptability of the intervention, and a full-scale trial will be assessed using a number of outcomes, including adherence to, and engagement with the intervention, recruitment and retention rates, proportion of missing data for each outcome measure, participants' experiences of the intervention and study, and coaches' experiences of delivering intervention support. Quantitative and qualitative findings will be integrated and summarised to contribute to the interpretation of the main feasibility evaluation findings. Value of information methods will be used to estimate the decision uncertainty associated with the intervention's cost-effectiveness and determine the value of a definitive trial. ETHICS AND DISSEMINATION: Ethical approval was received from Cambridge South Research Ethics Committee on 15/03/2021 (21/EE/0024). This protocol (V.2) was approved on 19 April 2021. Findings will be published in peer-reviewed scientific journals and communicated to other stakeholders as appropriate. TRIAL REGISTRATION NUMBER: ISRCTN12685964.