Table 3. Suggestion of BCS features.

No.	Themes	Behavior Change Strategy	App Feature/ Aspect of Design
1.	Instilling Self-Awareness	• Provide information about behavioral health links. • Provide information on consequences. • Provide feedback on performance	• Daily/weekly/monthly summaries of performance • Health tips or articles on the dangers or benefits of consuming too much or too little of certain foods.
2.	Closed Online Group Support	• Provide information about others’ approval • Provide opportunities for social comparison	• Leaderboard • Forums • Link to share the diet app with friends.
3.	Shaping Knowledge	• Provide instruction	• Recipes and articles on how to prepare healthy meals. • Health tips on how to incorporate more of certain food into one’s diet.
4.	Personalization	• Prompt specific goal setting • Set graded tasks • Prompt practice	• Provide suggestions for goals and tasks which users may choose (e.g., A range of weight that users may safely lose or gain in one month). • Suggest new goals based on users’ progress (e.g., milestones and badges) • Allowing users to enable or disable reminders, notifications, and certain features (i.e., Privacy settings, mental health reminders).
5.	User-Friendly Design	*This theme does not correlate with any BCS in particular but is still an important aspect of design to engage with diet app users.	• Simple but attractive colorway. • Clear illustrations (e.g., Graphs and diagrams) which are easy to understand.