Study population
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The sample size was calculated for the primary outcome of weight reductionParticipants of the intervention group and control group were recruited in two separate small municipalities (‘intervention municipality’ and ‘control municipality’) to keep the participants of the control group unaware of the lifestyle recommendations given to the intervention group. The complex real-world approach of our study, required involvement of local stakeholders within the ‘intervention municipality’As with all lifestyle interventions, blinding of participants or instructors to group allocation was not possible (as described previouslyParticipants ≥ 18 years who were capable of understanding the study content were included. The study was conducted in accordance with the Declaration of Helsinki and was approved by the ethics committee of the Westphalia-Lippe Medical Association and the Muenster University (Muenster, Germany; reference: 2017-105-f-S; approved 5 April 2017). All participants provided written informed consent.