Sweet check: Development and validation of a mobile app for dietary sugar monitoring using a design thinking approach

Objectives: Dental caries is strongly associated with excessive dietary sugar intake, and although the Sweet Score is a validated assessment tool, its manual calculation is time-consuming and prone to reporting bias. This study aimed to develop and validate a user-friendly mobile application to automate Sweet Score calculation and facilitate dietary sugar monitoring using a structured design thinking approach. Methods: The Double Diamond design thinking framework was employed. During the discover phase, literature review and content analysis of existing dietary applications were conducted along with a need assessment involving 10 target users. In the define phase, expert and user inputs were synthesized to establish functional requirements, including bilingual support, visual aids, and oral health education modules. The develop phase involved building the application on Android Studio incorporating 24-hour dietary recall, automated Sweet Score computation, personalized dietary tips, oral hygiene modules, and support features. In the deliver phase, a minimum viable product was finalized and tested. Face and content validity were assessed by 10 experts and 10 users, while usability testing was performed using the System Usability Scale (SUS). Results: The mobile application demonstrated high validity, with scale content validity indices of 0.98 among experts and 0.96 among users. Usability testing yielded a high SUS score of 87.75, indicating excellent user satisfaction and acceptance. Users reported positive feedback regarding real-time dietary feedback, portion visualization features, and integrated oral health guidance. Conclusions: The validated Sweet Check application provides an efficient and user-friendly platform for dietary sugar assessment and oral health promotion. The tool shows potential for large-scale public health implementation and integration into national nutrition and oral health programs.