The SWEET project (Sweeteners and sweetness enhancers: Impact on health, obesity, safety and sustainability) has been designed to i) identify and address the barriers and facilitators to the use of sweeteners and sweetness enhancers (S&SEs) and ii) examine the risks and benefits of using S&SEs to replace sugar in the diet in the contexts of health, obesity, safety and sustainability. Industry experts will integrate technological, health and sweetness databases to provide a platform on which new and emerging S&SEs can be selected for inclusion in food products. The behavioural and physiological impact of specific S&SEs will be examined in acute and repeated dosing studies and natural population differences (by age, region, gender etc) in sweetness perception established. A sensory profile will be developed and genetic determinants assessed. The core randomised controlled trial will adopt a whole diet approach to examine the impact of prolonged sugar replacement on weight control, appetite and energy intake. Underlying mechanistic effects of S&SE use, alone and in combination, will be evaluated using the technology platform developed in acute studies. Outcomes relating to safety and overall health risks will be i) measured in acute and chronic studies and ii) investigated in secondary data (long term interventions, prospective cohorts). The preferences for and perceptions of S&SEs within European consumers, and the barriers to their acceptance, consumption and use will be determined. The environmental cost and sustainability of replacing sugar with S&SEs will also be modelled. Consumers will be engaged to inform research design, and stakeholder driven exploitation and impact plans will be developed to communicate and disseminate project objectives and results to i) address the role of sweeteners in weight control for target audiences (consumers, health professions, scientists, policy makers, regulators) and ii) move effective products nearer to market. A gender action plan will be developed and implemented to promote equity across all research activities.