Background Dietetics mobile health apps provide lifestyle tracking and support on demand. Mobile health has become a new trend for health service providers through which they have been shifting their services from clinical consultations to online apps. These apps usually offer basic features at no cost and charge a premium for advanced features. Although diet apps are now more common and have a larger user base, in general, there is a gap in literature addressing why users intend to use diet apps. We used Diyetkolik, Turkey’s most widely used online dietetics platform for 7 years, as a case study to understand the behavioral intentions of users. Objective The aim of this study was to investigate the factors that influence the behavioral intentions of users to adopt and use mobile health apps. We used the Technology Acceptance Model and extended it by exploring other factors such as price-value, perceived risk, and trust factors in order to assess the technology acceptance of users. Methods We conducted quantitative research on the Diyetkolik app users by using random sampling. Valid data samples gathered from 658 app users were analyzed statistically by applying structural equation modeling. Results Statistical findings suggested that perceived usefulness (P<.001), perceived ease of use (P<.001), trust (P<.001), and price-value (P<.001) had significant relationships with behavioral intention to use. However, no relationship between perceived risk and behavioral intention was found (P=.99). Additionally, there was no statistical significance for age (P=.09), gender (P=.98), or previous app use experience (P=.14) on the intention to use the app. Conclusions This research is an invaluable addition to Technology Acceptance Model literature. The results indicated that 2 external factors (trust and price-value) in addition to Technology Acceptance Model factors showed statistical relevance with behavioral intention to use and improved our understanding of user acceptance of a mobile health app. The third external factor (perceived risk) did not show any statistical relevance regarding behavioral intention to use. Most users of the Diyetkolik dietetics app were hesitant in purchasing dietitian services online. Users should be frequently reassured about the security of the platform and the authenticity of the platform’s dietitians to ensure that users’ interactions with the dietitians are based on trust for the platform and the brand.

BACKGROUND Nutrition and fitness mobile health applications (mHealth apps) provide tracking and support mechanism on demand and it became a new trend for health service providers to shift into mHealth apps. Those services come to end-users with no cost to use but premium services into the apps can be purchased with an additional cost. Although Turkey’s most commonly used diet platform Diyetkolik, in its 7th year, is now more engaging with their users, customers’ behavioural intention to use these innovative apps is unknown. OBJECTIVE The aim of this study is to investigate influencing factors on nutrition-based mobile-health service to find out the behavioural intentions of users to adopt that kind of apps. To work on the issue, perceived usefulness, ease of use, price-performance, perceived risk, and trust factors were explored to assess the extended technology acceptance model. METHODS We conducted quantitative research methodology on the app users by using random sampling and valid data sample gathered from 658 app users were analysed statistically to investigate the framework by applying structural equation modelling (SEM). RESULTS Statistical findings suggested that perceived usefulness, perceived ease of use, trust, and price-performance have a significant relationship with behavioural intention. But, the relation between the observed risk factor and behavioural intention has been statistically rejected in this research. Additionally, there were no statistically significant results for age groups, gender differences and previous categorical app experience on the intention to use the app. CONCLUSIONS This research provided precious insights into TAM literature and mobile-health app developers and managers to recognize their customs’ behaviours and apparent external factors. Effects of proposed factors showed significant intention to use the app, except perceived risk. However, moderating effects should be kept in mind when examining extended TAM- based interventions to understand perceived risk factor via application use.