Background
Combined lifestyle interventions (CLI) aim to help clients with weight-related health risks to change their physical activity levels and dietary behaviors. These long-term (2 year) interventions are mostly delivered through face-to-face sessions with limited use of eHealth technologies. To integrate eHealth into existing CLIs, it is important to determine how behavior change techniques (BCTs) are being used by health professionals in the online and offline treatment of overweight clients. Therefore, we conducted semi-structured interviews with providers and developers of online and offline CLIs.

Methods
Due to the COVID-19 restrictions all semi-structured interviews were organized online. We recruited professionals who had experience with the (1) provision of the traditional ‘offline’ CLIs, (2) provision of online CLIs and (3) the development of (online) CLIs. The interview guide contained topics about the use and requirements of online and offline BCTs in practice. The data were analyzed through an inductive thematic approach.

Findings
Thirty-eight lifestyle professionals were interviewed. Professionals who work online use diary apps, smartwatches or smartphone-based accelerometers to support clients in changing their dietary and physical activity behavior. These tools help professionals in the provision of specific BCTs, including monitoring, feedback and shaping knowledge. Monitoring is seen as a starting point for feedback. Professionals use online modules to enhance knowledge about health consequences of unhealthy behavior. Coaches who work predominantly offline use goal setting and action planning techniques. Although online contact can be a quick and easy way to interact, physical meetings are seen as the best way to enhance social support.

Conclusion
These Findings suggest that it may be beneficial to use monitoring devices to provide just-in-time feedback based on the client’s actual performance. Based on the Findings we are now developing an online platform with instructions for lifestyle coaches how to integrate online BCTs into practice.