12-week weight loss programme. The 12-week Weight Loss Programme (WLP) will be based on the current successful UK-based dietician-designed nutritional knowledge and group work programme used within the Kissileff Laboratory, the content of which will be enhanced by a social cognition based programme currently used in Colorado. This employs a group based approach (10-12 participants) with frequent meetings (one per week) for a one hour session with a dietician trained researcher who will supervise the sessions and who will provide materials and 'home work' for the participants to complete before their next session. This programme will be tailored for the UK and specific behavioural components such as advice on self-monitoring, stimulus control, stress management, slow eating rate and related behaviours will be covered. An exercise component will also be included in which exercise activities are noted in a log and an additional online daily drinking log will also be included. The exercise log will be completed weekly and brought to each session as a means of monitoring. Weight will be measured at the start and end of this phase and weekly during the WLP as part of group sessions (at the end of the group session) and will be conducted privately with each participant in a separate room. Participants will also be asked to complete food frequency questionnaires (FFQs) once per month and online 3-day diet diaries before beginning the WLP and at the end of the WLP and will be given instructions on how to do so. In week 12 a further visit (independent from group sessions) will be scheduled individually with each participant to complete additional questionnaire and cognitive measures (Visit 13).