Most adults who try to lose weight fail to maintain it. Obesity is a key economic and healthcare challenge for Europe. Effective interventions and commercial programmes for weight loss are widely available, but most people re-gain their lost weight. Currently few comprehensive solutions exist to help Europeans manage weight loss maintenance (WLM). Current research suggests the most promising evidence-based behaviour change techniques for WLM are self-monitoring, goal setting, action control, building self-efficacy and intrinsic motivation. Recent research also suggests that stress management and emotion regulation skills are key enablers of relapse prevention and weight-regain. Information technology offers attractive tools for teaching and supporting these techniques, some of which are currently delivered through resource-intensive face-to-face therapies. ICT-delivery includes networked-wireless tracking technologies, weighing-scales and activity sensors, online tools and smart-phone apps, multi-media resources and internet-based support. A broad choice of tools is most likely to be acceptable to users, who can pick and choose their own preferred technologies. The NoHoW project tests whether ICT-based delivery of the most promising evidence-based behavior change techniques is effective for WLM. We will carry out a large-scale international 3-centre trial of information technology tools that implement the most up-to-date behavioural science research. This trial will establish the effectiveness of these ICT tools in supporting WLM, linked to studies of European consumer needs and behaviour. Impact: The project will directly feed results into development of new products and services from the UK’s largest commercial weight-loss provider, Slimming World providing immediate benefit to 500,000+ consumers. Commercialisation of project results will provide much needed WLM services that promote health education and long-term weight management programmes.