A Systematic Literature Review of Critical Features and General Issues of Freely Available mHealth Apps For Dietary Assessment

Obesity is known to lower the quality of life substantially. It is often associated with increased chances of non-communicable diseases such as diabetes, cardiovascular problems, different types of cancers, etc. Evidence suggests that diet-related mobile applications play a vital role in assisting an individual in making healthier choices and keeping track of food intake. However, due to an abundance of similar applications, it becomes pertinent to evaluate each of them in terms of functionality, usability, and possible design issues to truly determine state-of-the-art solutions for the future. Since these applications involve implementing multiple user requirements and recommendations from different dietitians, the evaluation becomes quite complex. Therefore, this study aims to review existing dietary applications at length to highlight key features and problems that enhance or undermine an application's usability. For this purpose, we have examined the published literature from various scientific databases of the CINAHL, Science Direct, and PUBMED. Out of our findings, fifty-six primary studies met our inclusion criteria after filtering out titles, abstracts, and full text. A total of 35 apps are analyzed from the selected studies. Our detailed analysis concluded the comprehensiveness of freely available mHealth applications from users and dietitians' frames of reference. Furthermore, we have also specified potential future challenges and stated recommendations to help develop clinically accurate diet-related applications.