Mobile app for fitness startup — 2

I am looking to have an iOS app created for my fitness startup. I specifically need the app to have a diet planner feature and require an online payment method. This diet planner will help users stick with their diet plans, track calories, and get helpful tips and advice from experts. Furthermore, users must be able to make payments online for the services provided by the app. The app must also be designed in a way that it is user-friendly, aesthetically pleasing, and highly functional.