Let’s Grow+: A mHealth intervention to enhance nutrition and movement behaviours in toddlers.

Intervention content will be delivered via an app (named “Let’s Grow”) and push notifications. Participants in the intervention group will work through 8 behaviour change modules within the app at their own pace and in whatever order they choose. Each module contains content on parenting and a combination of nutrition and movement behaviours (physical activity, sedentary behaviour and sleep) provided via infographics and short videos. Each module also contains a range of behaviour change activities for families to undertake online (e.g. create a bedtime routine), offline (e.g. practice a fundamental movement skill daily for a week) and a combination of both (e.g. app helps set a goal around increasing vegetable intake, attaining the goal occurs offline with notifications prompting and supporting goal adherence). In addition, core content is contained within an "Explore" page e.g. parenting strategy videos, play ideas, recipes. Intervention content has been developed by a team of experts and incorporates practical advice, established behaviour change techniques (e.g., goal setting, self-monitoring), and tips and tools to assist parents/caregivers to improve their child’s nutrition, physical activity, sleep and sedentary behaviour. Module content takes approximately 10min to read/view; the behaviour change activities conducted offline with assistance from notifications are undertaken over a period of up to 3 weeks per module. The intervention phase will last 6 months. Parents will also receive push notifications over the course of the intervention to assist with monitoring progress of ongoing activities (e.g. goal setting and self monitoring), to remind them of key messages, and to push them back to app content. Notifications will be personalised to include the parent and child names and their chosen goal/s (where appropriate). Intervention adherence will be monitored by app usage data. An automated notification will be sent 1 week after first log in if no modules have been started, to encourage participants to engage and complete the program. If there is continued inactivity, research staff will contact participants to encourage continuation of the program.