I'll try to explain in words how I got unlimited energy:
First, exit the game and close it from your running apps if that makes sense. Then, go onto your settings and go to date and time. Set the date to a day forwards. Afterwards, open the game and when it says "loading..." under that box that gives you tips on the game, exit the game immediately (DON'T close it from your running apps!!). The trick to this is to not let the game load. Then, go back to date and time and change the date back to the current day. Go back onto the game.
You'll see that you still don't have energy, right? Exit the game (don't close it from your running apps!) and go back onto the game again. You should have full energy :)
Please tell me if you still need help!
(ETA: This should work for Apple and Android)