Aim: To evaluate recall and response to the LiveLighter campaign and determine the population impact on behaviours and intentions related to weight reduction and its antecedents. Also, to investigate potential unintended consequences of the campaign.

Method: A pre-campaign baseline cross-sectional telephone tracking survey was undertaken with a random sample of adults aged 25 to 49 years (n=2,013) and repeated following each of the two media waves (n=2,010 each) in Western Australia (intervention state) and Victoria (comparison state). A cross-sectional online post-campaign survey of 13 to 17 year olds was also undertaken in the intervention (n=527) and comparison states (n=552).

Results: Top of mind recall was high (32%) and maintained despite a reduced media buy in the second wave and engagement with the campaign message increased. LiveLighter was more likely to reach overweight adults following the first wave and overweight adults were consistently more likely to perceive the campaign was personally relevant. LiveLighter resonated with females and parents but did not differentially reach adults by SES or geographic location. Tests of interaction models (state by time) showed positive changes in awareness of the harms to health of being overweight (p<0.05) and increased intentions to engage in recommended physical activity levels (p<0.05). No change was found in weight loss urgency or self-efficacy (p>0.05). There was no difference among adolescents between the states in body satisfaction, maladaptive weight loss approaches or held stereotypes about overweight people (p>0.05).

Conclusion: LiveLighter reached the intended target audience and shows no signs of wear-out. There were intermediate impacts on awareness and intentions related to weight loss and its antecedents associated with the campaign, but not yet more distal effects. The changes nevertheless provide evidence of the positive impact of the campaign. It also appears that the campaign did not place adolescents at increased risk of negative consequences.