BackgroundWith 1 in 4 Canadian preschoolers considered overweight or obese, identifying risk factors for excess weight gain and developing effective interventions aimed at promoting healthy weights and related behaviours among young children have become key public health priorities. Despite the need for this research, engaging and maintaining participation is a critical challenge for long-term, family-based studies. The aim of this study is to describe the implementation and evaluation of a parent-only advisory council designed to engage participants in the implementation and evaluation of a longitudinal, family-based obesity prevention intervention.MethodsA Family Advisory Council (n = 14 parents, 70% mothers, 64% white), was established to engage participant stakeholders in decisions related to research protocols and strategies to engage and sustain family participation. Using a mixed methods approach, including a participant survey and focus group, we examined the council members’ perceptions of their role and the impact this novel integrated Knowledge Translation (iKT) strategy had on the Guelph Family Health Study (GFHS), a longitudinal family-based study.ResultsAll members of the Family Advisory Council felt the topics discussed were appropriate, felt that their opinions were valued and that their suggestions have had an impact and direct benefit on the GFHS. The addition of the Family Advisory Council led to changes in study protocol (i.e. creation of more detailed intervention emails, creation of kid-friendly accelerometer bands) that may have contributed to the high retention rate of the GFHS (95% at 6-month follow-up).ConclusionsEngaging parents as research partners in family-based research studies may be an effective way to increase participant engagement and study retention.