There is little systematic review evidence to inform weight management programmes for adults with severe obesity (body mass index of 35kg/m2 or over). People with severe obesity are likely to need more assistance with weight loss and more likely to have medical, psychological and social problems related to their obesity.

This 20 month long project was funded by the National Institute of Health Research Health Technology Assessment Programme. This was a collaborative project between the Health Services Research Unit and Health Economics Research Unit (University of Aberdeen), Professor Marijn De Bruin, Health Psychology (University of Aberdeen), Professor Paul Aveyard, Department of Primary Health Care Sciences (University of Oxford) and Dr Laura Webber and Dr Lise Retat (UK Health Forum).

The project comprised a series of systematic reviews of randomised and non-randomised trials, qualitative research and health economic studies, to develop an economic model and inform the management of adults with severe obesity. We examined the effectiveness and cost-effectiveness of different approaches to helping change lifestyles, and compare lifestyle approaches to bariatric surgery. We used new methods to examine the behaviour change techniques which are most able to support people.