The Traffic Light Method (TLM) is a web tool originally developed as a practical tool for nurses and patients in one Dutch mental health care organization (GGz Centraal) and further advanced by a small spin-off company (Charly Green, Bilthoven, The Netherlands). It is based on the current state of the art of effective interventions and (inter)national guidelines on healthy lifestyle behaviour. During development, it was extensively reviewed by experts from the field in a Delphi panel and its use was optimized in a pilot study at GGz Centraal . The web tool is, after registration, available online (www.leefstijlinbeeld.nl; for a preview, see Fig. 2a and b).Fig. 2 a and b Preview of the web tool Traffic Light Method (TLM). Legend: a the starting page of the lifestyle behaviour screening representing the domains discussed in the Traffic Light Method (TLM) web tool; b examples of questions in the dietary domain within the lifestyle behaviour screening with built-in features to increase awareness (colouring according to risk profile) and knowledge (green bars presenting healthy reference values according to (inter)national guidelines)