Large Scale Implementation of MINISTOP 3.0

MINISTOP is an evidence-based app for parents of preschool aged children with the overall aim to promote healthy lifestyle behaviors and prevent the development of overweight and obesity. MINISTOP has been previously been evaluated in two previous trials (MINISTOP 1.0 and 2.0) with promising results. Therefore, the overall aim of this trial is to evaluate the large scale implementation of MINISTOP within Swedish primary child healthcare. The specific aims are to:(i) To evaluate the effectiveness of two different implementation strategies for MINISTOP 3.0 (i.e., Basic vs. Enhanced) on: the acceptability, appropriateness, feasibility as well as organizational readiness to implement MINISTOP 3.0 within primary child healthcare (primary outcomes) as well as the reach, costs, adoption, fidelity, and sustainability of MINISTOP 3.0 within primary child healthcare (secondary outcomes).(ii) To investigate the effectiveness of two different implementation strategies of MINISTOP 3.0 within primary child healthcare on children's key dietary indicators, physical activity, and screen time.(iii) To investigate the long-term effectiveness of MINISTOP 3.0 on children's BMI z-scores.(iv) To evaluate the cost-effectiveness of two different implementation strategies for MINISTOP 3.0.

Inclusion Criteria:Children and their parent(s) at the routine visit at 2.5/3-years of age at participating primary child healthcare centers in Sweden.Exclusion Criteria:Children from families who will not be able to understand the content of the MINISTOP 3.0 app (i.e., those that do not speak Swedish, English, Somali, or Arabic).Children who have been diagnosed with a endocrine or neurological disorder.Children who have a parent(s) suffering from a physical or psychological diseases which would make the study too demanding for them.