Degree Name

Doctor of Philosophy


Early Start


Background: eHealth childhood obesity treatment and prevention programs have shown promising results in facilitating behavior change, but there has been a lack of parent-focused studies and those that have included younger children.

Aim: The aim of this thesis was to investigate the efficacy of the Time2bHealthy online program in facilitating behavior change among preschool-aged children who are overweight, or at risk of becoming overweight.

Methods: A systematic review and meta-analysis on eHealth parent-focused childhood obesity prevention and treatment interventions were conducted and gaps in the literature were identified. A randomized controlled study was then designed, implemented and evaluated to test the efficacy of the Time2bHealthy online healthy lifestyle program for parents of 2-5 year old children. Parent/carer and child dyads were recruited from areas of New South Wales and Victoria, Australia between 2016 and 2017 and randomized to an intervention or comparison group. The intervention consisted of an 11-week online healthy lifestyle program and participants then received fortnightly emails for the following 3-months. Participants also had access to a closed Facebook group. Comparison participants were sent emails with links to information on similar topics. The primary outcome assessed was child body mass index (BMI). Secondary outcomes included child dietary intake, physical activity, screen-time, sleep, child feeding, parent modelling and self-efficacy. Data were collected at baseline, 3- and 6-months by data collectors blinded to group allocation. Following the collection of baseline measures, randomization was conducted using a computerized random number generator. A process evaluation of the Time2bHealthy online program was conducted to test user acceptance. Outcome data were further explored to investigate if change in child BMI at 6-months post-baseline was moderated by demographic characteristics or mediated by changes in obesity-related variables at 3-months post-baseline. Finally, the effect of engagement in the Facebook group on the primary and secondary outcomes was assessed by using a high and low engagement definition to categorize participants.

Results: Eighty-six parent/carer and child dyads were recruited to the trial in six cohorts. A retention rate of 91% was achieved, with 78 dyads attending the 3- and 6-month follow-ups. Seven participants were lost to follow-up and one withdrew from the trial. The mean child age was 3.46 years and 91% of children were in the healthy weight range. The intention-to-treat analyses found no significant change in child BMI between groups. Compared to children in the comparison group, those in the intervention group reduced their frequency of discretionary food intake (estimate -0.360, 95% CI -2.272 to -0.447, P=0.004), and parents in the intervention group improved their child feeding pressure to eat practices (-0.304, 95% CI 0.061 to -0.003, P=0.048) and parent self-efficacy (nutrition) (0.429, 95% CI 0.096 to 0.763, P=0.012) compared to those in the comparison group. There were no significant group by time interactions for other outcomes. The process evaluation indicated a high level of user acceptance. The mediation and moderation exploratory analyses found that there were no significant mediators or moderators of child BMI change in the models that were tested. Most intervention participants joined a Facebook group and the majority moderately engaged in their group. There was no significant difference in BMI change between the participants who highly engaged in Facebook compared to participants who had a lower level of engagement. Positive outcomes were demonstrated for parents who highly engaged in Facebook compared to those who had a lower engagement level in relation to percentage sedentary time (estimate -2.972, 95% CI -5.714 to -0.230, P 0.035) and sleep duration (estimate 0.401, 95% CI 0.031 to 0.771, P 0.035) of their child. There was a significant group by time interaction in relation to kilojoule intake per kg of body weight in the non-hypothesized direction (estimate 86.824, 95% CI 22.136 to 151.512, P=0.010).

Conclusion: This thesis provides an important contribution to the literature on eHealth parent-focused childhood obesity interventions. The Time2bHealthy randomized controlled trial demonstrated that a parent-focused eHealth childhood obesity prevention program did not demonstrate a difference in child BMI between groups, but did facilitate improvements to dietary-related practices and parent self-efficacy. The program content and mode of delivery were also well accepted by parents. The null findings in relation to child BMI change between groups was possibly due to most children in the sample being in the healthy weight range. It is recommended that future studies include a larger sample size and longer follow-up period. Potential scalability and translation of the program into the community should also be explored.

FoR codes (2008)




Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.