NIHR explores the evidence behind the research behind obesity as a major public health concern across the UK and internationally
Why was this study needed?
Obesity is a major public health concern across the UK and internationally. In 2016, 26 per cent of men and 27 per cent of women in England were obese, and a further 40 per cent of men and 30 per cent of women were overweight. People who are overweight or obese have a much greater risk of developing type 2 diabetes, heart disease and stroke, joint problems and some cancers. The risks associated with obesity can be substantially reduced with as little as five percent of body weight loss. Group lifestyle approaches to weight loss have potential to save money and offer peer support to participants, and the reviewers aimed to look at the combined interventions delivered in groups.
What did this study do?
This study was a systematic review of randomised controlled trials of group-based diet and physical activity interventions. It included adults from the general population who were overweight or obese (defined as BMI 25 kg/m2 or more, or BMI more than 29 kg/m2 respectively). Sixty separate group-based interventions were described in 47 trials, with 10,703 participants. Interventions involved changes in diet and physical
In 2016 27% of women were obese
activity combined, diet alone, or exercise behaviour alone. Interventions were delivered in a range of settings including the community (football clubs), healthcare settings (primary care practices), universities and work sites. Interventions used tools such as diaries, apps and pedometers; and education and support through printed materials, email or phone, or face to face. The main outcome was weight loss compared with a control group not receiving the intervention, at the follow-up points closest to six, 12 and 24 months from baseline. The mixed quality of included trials means that these results are unreliable and the variety of approaches limit conclusions about exactly how effective group interventions work and what the effective components might be.
What did it find?
- Overall, group-based interventions had a greater weight loss by 3.5 kg at six months (95 per cent confidence interval [CI] -4.2 to ‑2.8), 3.4kg at 12 months (95 per cent CI -4.2 to -2.9), and 2.6 kg at 24 months (95 per cent CI -3.8 to -1.3).
- Explicitly targeting weight loss and including feedback and diet goals/plans were significantly associated with intervention effectiveness.
- Group-based interventions delivered to men only were on average twice as effective as those to women only (average weight 5.5 vs 2.6 kg). Mean attendance was 67 per cent, as reported for 41 interventions (range 21–87 per cent).
What does current guidance say on this issue?
In general, multi-component lifestyle interventions, incorporating dietary, physical activity and behavioural components, are central to the recommendations of NICE guidelines and NICE public health guidance on obesity management. NICE public health guidance from 2014 recommends that group lifestyle-based interventions are offered if an individual does not have a preference for individual attention.
What are the implications?
Group-based diet and physical activity programmes for overweight and obese people can achieve modest weight loss. Group programmes can be more beneficial when they explicitly target weight loss, include separate groups for men only, and involve feedback and specific diet goals/plans. The NIHR Dissemination Centre has published a research highlight on managing obesity in men. Those designing programmes will need to consider the characteristics of these effective programmes and the behavioural change techniques they use. However, different group approaches seem to have broadly similar benefits and have the potential to be cheaper per head and therefore more a efficient use of resources compared with individual support.
Expert view:
Anna Young specialist physiotherapist and weight management lead at Homerton University NHS Trust
There is a rising concern amongst health care professionals regarding plus-sized bodies within the UK. Many health conditions associated with high body weight over a long time can result in a need to access health services, a reduced quality of life and stigma in those struggling to manage their weight.
Group-based lifestyle interventions offer a supportive and informative environment that is evidence based and can be effective for those motivated to manage their weight but struggling to make sustainable changes.
The study highlights that there are many group-based programmes in the UK with a mixed approach such as length of programme, the educational content and professionals delivering such groups.
Those groups with better weight loss outcomes should be reviewed in greater detail so that good practice can be shared or indeed standardised. Multi-component programmes with nutrition, physical activity and psychological support targeting specific groups seem to be more effective and should be considered in the design.
Bibliography: HSCIC. The health survey for England 2016 - adult overweight and obesity. London: Health and Social Care Information Centre; 2016. NHS website. Obesity. London: Department of Health and Social Care; 2016. NICE. Weight management: lifestyle services for overweight or obese adults. PH53. National Institute for Health and Care Excellence; 2014. NIHR DC. Managing obesity in men. Southampton: National Institute for Health Research Dissemination Centre; 2016. Robertson C, Archibald D, Avenell A, et al. Systematic reviews and integrated report
on the quantitative, qualitative and economic evidence base for the management of obesity in men. Health Technology Assessment. 2014;18(35). Shaw KA, Gennat HC, O’Rourke P, Del Mar C. Exercise for overweight or obesity. Cochrane Database Syst Rev. 2006;(4):CD003817.
Citation and funding: Borek AJ, Abraham C, Greaves CJ, Tarrant M. Group-based diet and physical activity weight-loss interventions: a systematic review and meta-analysis of randomised controlled trials. Appl Psychol Health Well Being. 2018;10(1):62-86.This project was funded by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care of the South West Peninsula (PenCLAHRC), C. Greaves’ Career Development Fellowship (CDF-2012-05-029), and A. Borek’s PhD scholarship from the University of Exe
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