The intensive weight-loss (IWL) intervention is designed to adapt to participants' needs, and is intended to ensure large and sustained weight loss to improve physical and mental health. IWL intervention offers an individualised combination of total meal replacement, behavioural support, physical activity, and possibly pharmacological treatment.

We will conduct three large-scale, high-quality, randomised controlled trials to evaluate the effects on body weight, cardiometabolic health, quality of life, safety, and cost-effectiveness of the IWL intervention compared with current management strategies in both primary and secondary care.

The three trials differ in terms of the participants, primary and secondary outcomes, and the treatment comparators, reflecting differences in existing obesity management programmes (usual care). In the LightCARE trial the IWL intervention is compared with usual care in primary care for people with obesity. The LightWAY trial also compares the IWL intervention with usual care for people with severe and complex obesity. Finally, the LightBAR trial compares the IWL intervention with bariatric surgery in patients eligible for surgery.

These trials involve municipalities and local health boards, general practitioners and hospitals, which means that the intervention for management of obesity will be tested across the healthcare system in both Denmark and the United Kingdom. This also allows us to test  whether the new treatment approaches are a cost-effective alternative to existing obesity management strategies. In Denmark the intervention will be delivered through a dedicated hub structure established in three municipalities: Hvidovre, Gladsaxe and Frederiksberg. The municipality-based hubs deliver the intervention using both in-person and remote approaches, support by healthcare professionals in close collaboration with other local health services and general practitioners. In the United Kingdom the intervention will be delivered remotely by private healthcare providers. ​