Participant profile and impacts of an Aboriginal healthy lifestyle and weight loss challenge over four years 2012-2015.

Objective: To explore participation, consistency of demographic and health profiles, and short-term impacts across six Aboriginal Knockout Health Challenge (KHC) team-based weight loss competitions, 2012 to 2015.

Methods: Data comprised one competition each from 2012 and 2013 and two per year in 2014 and 2015. We compared baseline and change (pre- to post-competition) in weight, fruit and vegetable consumption, physical activity and waist circumference (baseline only) across competitions using mixed models.