Adults Regulating Their weight Everyday with Mobile Internet Support (ARTEMIS) is a randomised, controlled trial examining the effectiveness of the self-regulation intervention to promote weight loss, when delivered through a mobile application, with no in-person contact, among a sample of \~ 1,294 adults living with obesity in the United Kingdom. Further, the investigators will assess the safety of the intervention regarding any a potential unintended consequence, which is the development of disordered eating. The intervention comprises daily self-weighing and daily reflection on the day's task of controlling weight through implementation of actions, and selection of new actions for the next day. It encourages users to build up a repertoire of actions for life that suit them in controlling weight.