Participants were invited to take part in this study based on their registration in the tier 3 bariatric service at the Royal Derby Hospital and a score of more than 6 in the binge eating survey previously completed as part of their clinical care. the invistigators invite 30-40 participants to participate in this study.

After the completion of the consent form participants will be asked to complete a safety questionnaire to check whether there are any known reasons tDCS would not be suitable for them. If it is suitable to participate in a tDCS study for obesity, participants will be randomised to either real tDCS or Sham tDCS (Sham tDCS is like a "fake" version of tDCS. It's used in experiments to make people think they're getting brain stimulation when they're not. This helps researchers see if the real brain stimulation has a genuine effect or if it's just because people believe it will work). The randomization process for group assignment will be conducted using a computer program, which means participants will not have the ability to select or choose their preferred group. participants will receive 6 sessions of real tDCS or sham for three weeks (2 sessions a week). the investigators will follow up with participants for two weeks after the study end. The follow-up procedure will involve the completion of questionnaires and the stop signal task once again. Additionally, body weight measurements will be taken during this stage. Therefore, they will participate for 8 weeks in this study. All sessions will take place in the University of Nottingham medical school at Derby Royal Hospital and University of Nottingham jubilee campus. The first and last session will take approximately 1.30 hours and the other sessions will last 40 minutes each. In the first and last sessions, participants will be asked to fill in 4 questionnaires (30 minutes to fill), doing an impulsivity test (also known as Stop Signal Task) (it is an easy test and will take 5 minutes. The stop signal task is a psychological test that measures participant ability to stop or pause a planned action when they're signalled to do so. It helps assess self-control and how well participants can inhibit or control their impulses) and receive one session of tDCS or sham (20 minutes). In the 4 sessions, the participant will only receive one session of real tDCS or sham. During the study (8 weeks) the participant will be asked to fill a daily food record using mobile app. After the end of the study, the participant will be asked to do an interview to talk about the experience of being in the study. The interview will be conducted at the end of the study either in person or online using Teams.

tDCS has no major safety concerns according to National Institute for health and Care Excellence (NICE 2015). The most frequent temporary side effects are mild tingling, slight itching, moderate fatigue, headache or, less frequently, a slight burning feeling. These effects usually develop at the start of the tDCS and disappear shortly after. Headaches, mild discomfort, or irritation on the skin generally involve slight discomforts that are promptly relieved by over-the-counter pain relief medicines. It is important to inform us of any side effects experienced after the tDCS sessions and to contact participant's GP or treating clinician with any healthcare concerns or study-related questions.

the investigators cannot promise the study will help the participant but the information that investigators get from this study may help to the advancement of scientific knowledge by expanding our understanding of the effects of tDCS on appetite regulation, cognitive control, and long-term behaviour modification in the context of obesity, potentially leading to the development of more effective treatments and interventions for weight management in the future.

the recruitment started on 01/03/2024 and the study end date will be 30/09/2025. this study was funded py the PGR office at the University of Nottingham.