You ARE indeed able to CREATE multiple profiles using the JEFIT Application either android or iOS.
When using JEFIT you will be able to log in and create one profile at a time. Creating a profile with JEFIT will require you to use a singular email address for each account.
Unfortunately you aren't able to use a singular email address to register multiple JEFIT Accounts.
If you want to create a second profile for your JEFIT Account you will navigate to the Preferences Page on the Android or iPhone Apps and just logout the current account that's logged in.
AFTER LOGGING OUT
Then after logging out of your JEFIT Account, you will be able to re-load the application, select the option to create a new profile.
When creating this second profile you will need to use an alternate email address and username.