Usability and Acceptability of a Digital Health App to Support Infant Feeding and Lifestyle Behaviors: Mixed Methods Pilot Study

Background: Childhood obesity is a global health concern with long-term cardiometabolic and psychosocial consequences. Establishing healthy feeding and lifestyle behaviors from infancy is critical to population health efforts with a life course perspective. Recently, digital health applications have gained traction in reaching out to parents and promoting healthy feeding behaviors. Objective: The aim of this study was to evaluate the usability and acceptability of the Feeding, Lifestyle, Activity Goals app in providing parents with evidence-based guidance and tailored advice to promote healthier eating behaviors and lifestyle habits among infants. Methods: We conducted a mixed methods pilot study among parents of infants aged 0 to 24 months recruited from a tertiary maternity and children's hospital in Singapore. Participants used the digital health app for 7 days. Usability was assessed using the validated System Usability Scale (score range 0-100, with ≥70 indicating acceptable usability). Acceptability was explored via open-ended questionnaires on satisfaction, relevance, and user experience, with qualitative data analyzed thematically by 2 independent coders to ensure rigor. Results: A total of 26 parents of infants aged 3 weeks to 23 months completed the study. The app demonstrated good usability, with a mean System Usability Scale score of 71.3 (SD 11.0). Parents valued its role in organizing infant care; promoting self-reflection on parenting practices; and providing personalized, evidence-based recommendations. These benefits were particularly appreciated by first-time parents and those with multiple caregiving responsibilities. Challenges included an unintuitive user interface, high manual data entry burden, and advisory content that was occasionally overly general or text heavy. These insights highlight clear priorities for onward efforts in optimization. Conclusions: Results of our mixed methods evaluation indicate that our digital health app demonstrated good usability and acceptability among parents of infants. Targeted refinements to the interface, data entry processes, and content delivery are warranted before large-scale evaluation to determine its impact on early-life health behaviors and obesity prevention.