AI Algorithms and processes

1). What AI algorithms and processes are needed in,order to develop a virtual athletic/fitness/personal trainer simulating the creation of customized workouts based off specific goals/parameters? 2). Secondy, what AI algorithms and processes are needed in order to develop a virtual nutritionist simulating the creation of a diet based on clients goals/expectations? 3). Lastly, what AI disciplines and algorithms would be used in the creation of a “magic mirror,” application where clients can upload pics and the mirror emulated3back the ideal body conditioning you want?