In recent years, the application on mobile has become widely used in various application fields e.g. game, finance, education, and so on because of its anytime anywhere ease of access. Also many health and fitness applications have been developed to take care oneself. Thus, this project aims to study diet application for android. The proposed system was developed to support to diet and exercise activity. We programmed the applications in Java built in Eclipse and connecting with SQLite for database part. To simulate android of mobile, our work uses the library of emulator. The ability of our system can manage information for user such as to suggest list of food for each meal, to suggest exercise activity, to notice the time to eat. Moreover, this project provides to calculate for body mass index (BMI), basal metabolic rate (BMR), and course to diet. Our project can provide the above information on mobile for diet or healthy user.