Since inactivity and unhealthy eating are amongst the biggest health problems of our era, weight monitoring applications are becoming favoured options. However, in order to ensure people's health and wellbeing, not only their physical state but also mental and social states should be supported by these applications. Recently, studies indicate the power of mobile applications in promoting health and wellbeing but there are still a limited number of studies about how these apps can be improved with the aim of better supporting wellbeing. For this reason, in this study, mobile diet apps were examined in the context of design for wellbeing. Three mobile diet apps were used by 15 participants who had an interest in healthy eating or weight loosing for one week. Three phased study was conducted to learn about the users' before and after weight control preferences and the strengths and weaknesses of the diet control apps. Consequently, suggestions were presented for improvement of weight control body monitoring apps with the aim of enhancing people's wellbeing.