Core outcome set for behavioural weight management interventions for adults with overweight and obesity: Standardised reporting of lifestyle weight management interventions to aid evaluation (STAR-LITE).

Behavioural weight management interventions in research studies and clinical practice differ in length, advice, frequency of meetings, staff, and cost. Few real-world programmes have published patient outcomes and those that have used different ways of reporting information, making it impossible to compare interventions and develop the evidence base. To address this issue, we have developed a core outcome set for behavioural weight management intervention programmes for adults with overweight and obesity. Outcomes were identified via systematic review of the literature. A representative expert group was formed comprising people with experience of adult weight management services. An online Delphi process was employed to reach consensus as to which outcomes should be measured and reported and which definitions/instruments should be utilised. The expert group identified eight core outcomes and 12 core processes for reporting by weight management services. Eleven outcomes and five processes were identified as optional. The most appropriate definitions/instruments for measuring each outcome/process were also agreed. Our core outcome set will ensure consistency of reporting. This will allow behavioural weight management interventions to be compared, revealing which interventions work best for which members of the population and helping inform development of adult behavioural weight management interventions.