Hi hello and welcome
Yes, your kitty will remain to need food wether you are online or not.
Kitties do no eat when they sleep and start to nibble from the available food again as soon as they wake up.
Should there be no food for three days the kitty becomes sick.
They luckily never die.
If your kitty becomes sick you have two options.
Let the kitty heal after it has access to food again: the recovery takes one week.
Or you can heal the kitty instantly with the "get well" vitamin.
Good luck with your kitty!
Welcome to KittyCatS again!
Kay